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Full text of "Bulletin of the British Museum (Natural History) Entomology"

Bulletin of the 

British Museum (Natural History) 



A review of the Solenopsis genus-group and 
revision of Afrotropical Monomorium 
Mayr (Hymenoptera: Formicidae) 

Barry Bolton 



Entomology series 

Vol 54 No 3 25 June 1987 



The Bulletin of the British Museum (Natural History), instituted in 1949, is issued in four 
scientific series, Botany, Entomology, Geology (incorporating Mineralogy) and Zoology, 
and an Historical series. 

Papers in the Bulletin are primarily the results of research carried out on the unique and 
ever-growing collections of the Museum, both by the scientific staff of the Museum and by 
specialists from elsewhere who make use of the Museum's resources. Many of the papers are 
works of reference that will remain indispensable for years to come. 

Parts are published at irregular intervals as they become ready, each is complete in itself, 
available separately, and individually priced. Volumes contain about 300 pages and several 
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the individual parts. Orders and enquiries should be sent to: 



Publications Sales, 

British Museum (Natural History), 
Cromwell Road, 

London SW7 5BD, 
England. 



World List abbreviation: Bull. Br. Mus. nat. Hist. (Ent.) 



©British Museum (Natural History), 1987 



The Entomology series is produced under the general editorship of the 

Keeper of Entomology: Laurence A. Mound 

Assistant Editor: W. Gerald Tremewan 



ISBN 565 06026 

ISSN 0524-6431 Entomology series 

Vol 54 No 3 pp 263-452 
British Museum (Natural History) 
Cromwell Road 
London SW7 5BD Issued 25 June 1987 



A review of the Solenopsis genus-group and 
revision of Afrotropical Monomorium Mayr 
(Hymenoptera: Formicidae) 

Barry Bolton 

Department of Entomology, British Museum (Natural History), Cromwell Road, London 

SW7 5BD 

Contents 

Synopsis 263 

Introduction and history 264 

Measurements and indices 268 

Depositories 269 

The Solenopsis-group 269 

Key to Solenopsis-group genera (workers) 271 

Anillomyrma Emery 273 

Bondroitia Forel 275 

Diplomorium Mayr 278 

Epelysidris gen. n 279 

Phacota Roger 281 

Allomerus Mayr 282 

Antichthonidris Snelling 283 

Nothidris Ettershank 284 

Megalomyrmex Forel 285 

Solenopsis Westwood 285 

Oxyepoecus Santschi 286 

Carebarella Emery 286 

Monomorium Mayr 287 

The Afrotropical fauna of Monomorium 301 

Key to Afrotropical species-groups (workers) 302 

Synonymic list of Afrotropical species 302 

Key to Afrotropical species (workers) 307 

The scabriceps-group 320 

The destructor-group 322 

The salomonis-group 329 

The setuliferum-group 365 

The monomorium-group 37 1 

The fossulatum-group 420 

The hanneli-group 425 

The latinode-group 429 

Acknowledgements 430 

References 430 

Index 450 



Synopsis 

A review is presented of the 13 genera currently taken to constitute the Solenopsis-group, which is 
redefined here. The genus-group in the sense of this paper includes three former groups, the Monomor- 
ium-, Megalomyrmex-, and Solenopsis-groups, combined. Extensive modifications to the genera formerly 
included in the first of these are proposed, including the new synonymy of Syllophopsis Santschi and 
Chelaner Emery under Monomorium Mayr, the reinstatement of Phacota Roger and Bondroitia Forel as 



Bull. Br. Mus. nat. Hist. (Ent.) 54 (3): 263-452 Issued 25 June 1987 



264 B. BOLTON 

valid genera, and the exclusion of Hagioxenus Forel from the group. The genera Tranopelta Mayr and 
Ochetomyrmex Mayr (= Brownidris Kusnezov) are newly excluded from the group and the previous 
provisional synonym of Monomorium, Xenoaphaenogaster Baroni Urbani, is transferred out of the group 
and newly synonymized with Pheidole Westwood. One new genus, Epelysidris, is described from Borneo. 
The status of Diplorhoptrum Mayr as a separate genus is considered and rejected and a key to recognized 
genera is presented. Treatment of individual genera varies from a short review of current knowledge to a 
redefinition and revision of some smaller genera (Anillomyrma Emery, Bondroitia Forel, Diplomorium 
Mayr). The very large genus Monomorium is reviewed and redefined on a world-wide basis and its 
extensive genus-level synonymy is discussed in detail. The former genera and subgenera now synonymized 
with Monomorium are fitted into a system of informal species-groups which are defined and discussed on a 
world-wide basis. A new name is proposed for the type-species of Monomorium, which is preoccupied, and 
the authorship and publication date of M. antarcticum (Smith) is investigated. The large Afrotropical fauna 
of Monomorium is fully revised and keyed, and contains 145 species in 8 species-groups. The latter are 
keyed separately and only two species-groups are confined to the Afrotropical region. Of the 145 species 
currently recognized as valid, 46 are described as new in this paper and 35 are newly elevated to 
species-rank from former infraspecific status; 43 new species-level synonyms are proposed, mostly of 
former infraspecific forms. 

Introduction and history 

This survey began as a taxonomic revision of the Afrotropical species of the large genus 
Monomorium Mayr. However, whilst examining the world fauna of this genus and its relatives 
prior to commencing the revision, it became apparent that much remained to be done, both at 
genus and genus-group level, with all the taxa related to Monomorium and Solenopsis 
Westwood. It is hoped that the results discussed here will help to dispel at least a little of the 
taxonomic and nomenclatural fog which still surrounds many genera, and perhaps clear the way 
for more detail systematic or phylogenetic work. 

The study presented here gives an historical review of the genus-level taxonomy of the group, 
redefines the group as I currently view it, and goes on to discuss each included genus in greater or 
lesser detail. For several genera this review amounts to little more than a short synopsis of recent 
developments, but several smaller genera are treated in greater detail and are redefined. The 
large genus Monomorium has received most attention and a summary and discussion of the 
genus and its synonyms on a world-wide basis is given prior to the formal revision of the large 
Afrotropical fauna. This last section is a continuation of the series aimed towards a revision of 
the Afrotropical Myrmicinae. Previous parts include Bolton 1976, 1980, 1981a, 19816, 1982, 
1983, 1985, 1986a. 

As conceived here, for the reasons discussed in detail below, the Solenopsis genus-group 
contains 13 genera, most of which are relatively small and of limited zoogeographical distribu- 
tion. Two genera are however very large and of world-wide occurrence, and include a number of 
extremely successful tramp-species. An idea of the sizes and rangs of the genera, in terms of 
endemic species, may be gleaned from the following table. The number of species in the larger 
genera is very much an approximation as their species-level taxonomy remains utterly uninvesti- 
gated over the greater part of their ranges. 

Genus Distribution Number of species 

Monomorium Mayr World wide (mainly Old World tropics) ca 300 

Solenopsis Westwood World wide (mainly New World tropics) ca 200 

Megalomyrmex Forel Neotropical 25-30 

Oxyepoecus Santschi Neotropical 11 

Allomerus Mayr Neotropical 4 

Carebarella Emery Neotropical 4 

Nothidris Ettershank Neotropical 3 

Anillomyrma Emery Oriental & Indo- Australian 2 

Bondroitia Forel Afrotropical 2 

Antichthonidris Snelling Neotropical 2 

Diplomorium Mayr Afrotropical 1 



SOLENOPSIS GENUS-GROUP 265 

Epelysidris Bolton Indo- Australian 1 

Phacota Roger Palaearctic 1 

Earlier attempts at a classification of the myrmicine ants by Emery (1895<i, 1915), Wheeler 
(1910), and Forel (1917) culminated in the classical systems proposed by Emery (1922) and 
Wheeler (1922). The last author included Solenopsis and all its supposed relatives in a single 
tribe, the Solenopsidini. Emery (1922) basically recognised all the same genus-level names as 
Wheeler, but divided the mass of genera into two tribes, Pheidologetini plus Solenopsidini, and 
further created a number of subtribes within each of these. 

The situation rested there without change until 1966, except for the addition of new genera 
and subgenera by various authors in the intervening years. Both of the 1922 classifications were 
unsatisfactory because of their vagueness of tribal-level definition. To some extent this was 
brought about by the inclusion of a number of disparate genera whose resemblances to 
Solenopsis or Monomorium were superficial and whose real affinities lay elsewhere. Also the 
problem of definition of the group was exacerbated by the fact that it was extensively used as a 
catch-all, to hold genera not obviously fitting anywhere else in the Myrmicinae. 

In his genus-level study of the ants related to Solenopsis and Pheidologeton Mayr, Ettershank 
(1966) gave a synopsis of the earlier attempts to formulate a classification for these difficult taxa. 
He tabulated a summary up to 1966 of all genera and subgenera applied to the groups in these 
previous surveys, and set his own revised classification alongside. In short, where earlier authors 
had recognized one or two tribes, namely Solenopsidini or Solenopsidini and Pheidologetini, he 
recognized four genus-groups. One of these, the Pheidologeton-group, corresponded almost 
exactly with the old tribe Pheidologetini in the sense of Emery (1922), except that Ettershank 
(1966) included Anisopheidole Forel in the group (transferring it from the Pheidolini) and 
excluded Trigonogaster Forel and Dyomorium Donisthorpe, rightly synonymizing the latter 
with Vollenhovia Mayr. The Pheidologeton-group is considered valid here and is retained to 
contain the six genera which Ettershank included, namely Anisopheidole, Carebara Westwood, 
Lophomyrmex Emery, Oligomyrmex Mayr, Paedalgus Forel, Pheidologeton, and their 
synonyms as currently listed (Ettershank, 1966). 

This group fits most of the characterization given for the expanded Solenopsis-group in 
the sense of this publication (see below), but two characters consistently differentiate the 
Pheidologeton-group from Solenopsis and its allies. 

(1) The median clypeal seta is universally lacking in the Pheidologeton-group. (2) The forewings 
of males and females in the Pheidologeton-group have a closed radial cell formed by the 
distalmost portion of Rs arching to the leading edge of the wing apicad of the pterostigma, where 
it fuses with the marginal apex of R and closes the cell. (Both these are considered plesiomorphic 
here, their apomorphic states being exhibited by the Solenopsis-group.) 

Other characters of interest in the Pheidologeton-group, but apparently not universal, include 
the following. The mandibles tend to have a straight masticatory margin which commonly meets 
the basal margin in a near right-angle, and the mandible usually has 5 or more teeth. (In the 
Solenopsis-group the masticatory margin tends to be oblique and usually has 5 or fewer, 
generally 4, teeth.) The antennal club is most frequently 2-segmented and the propodeum most 
often bears teeth or spines in the Pheidologeton-group. 

Despite Ettershank's (1966) exclusion of Trigonogaster from any of his groups I suspect that it 
may be derived from the Pheidologeton-group but isolated by its very specialized body form and 
much reduced wing venation. 

The tribe Solenopsidini in the sense of Emery (1922) was divided by Ettershank (1966) into 
the following three genus-groups. 

Monomorium-group: Anillomyrma, Chelaner Emery, Diplomorium, Hagioxenus Forel, 
Monomorium, Syllophopsis Santschi, and their included synonyms. 

Megalomyrmex-group: Allomerus, Brownidris Kusnezov, Carebarella, Megalomyrmex, 
Nothidris, Tranopelta Mayr, and their included synonyms. 

Solenopsis-group: Oxyepoecus, Solenopsis, and their included synonyms. 

Genera formerly included in the Solenopsidini but excluded prior to Ettershank's survey were 



266 B. BOLTON 

Tranopeltoid.es Wheeler, synonymized with Crematogaster Lund by Kempf (1960) ; and Adlerzia 
Forel, which Brown (1952) had transferred to tribe Pheidolini. Ettershank (1966) further 
excluded Vollenhovia (= Heteromyrmex Wheeler, = Dyomorium Donisthorpe, = Dorothea 
Donisthorpe), Xenomyrmex Forel (= Myrmecinella Wheeler), Liomyrmex Mayr, Huberia 
Forel, and Aner gates Forel from consideration in any of his genus-groups. All these exclusions 
are still considered to be correct and in part are supported by Kugler's (1978) findings relating to 
the sting structure in some of these genera. Further work on these disposals has shown that 
Anergates is a tetramoriine (Bolton, 1976), Huberia appears to be a member of the Myrmica- 
group of genera, and the other names form a genus-group of their own, the Vollenhovia-growp. 

Modifications to Ettershank's system published since its appearance in 1966 include the 
synonymy of Brownidris with Ochetomyrmex Mayr by Kempf (1975), the splitting of Nothidris 
in the sense of Ettershank (1966) into two discrete genera, Nothidris plus Antichthonidris , by 
Snelling (1975), and the removal of Hagioxenus as a junior synonym of the tetramoriine genus 
Rhoptromyrmex Mayr by Bolton (1986a). 

Concerning the three genus-groups devised by Ettershank from the old tribe Solenopsidini, 
Kempf (1974) expressed concern that they were 'too loosely defined, most of the diagnostic 
characters not being sufficiently exclusive.' This was brought about by his discovery of the first 
male of an Oxyepoecus species, which had affinity with Megalomyrmex rather than with 
Solenopsis, to which group it was supposed to belong. 

The present study implies that the three genus-groups of Ettershank are best recombined into 
a single unit, the Solenops w-group, but with the exclusion of the genera Tranopelta and 
Ochetomyrmex (= Brownidris). When establishing the latter genus-level synonym Kempf 
(1975) suggested that Ochetomyrmex be transferred into the solenopsidine tribal complex. 
However, both of these genera lack the median clypeal seta in all castes and the workers and 
females have the petiolar spiracle situated in front of the midlength of the peduncle. This 
combination of characters, taken together with Kugler's (1978) sting characters indicating that 
Tranopelta lies some distance from Solenopsis, Monomorium and their allies, seem to me 
sufficient to exclude Tranopelta and Ochetomyrmex from the Solenopsis-gvoup as defined 
below. 

Other characters shared by these two genera include, in the worker, large well-developed 
metapleural glands, broad clypeus which is not bicarinate, postpetiole broadly attached to the 
gaster and with a sharp anteroventral process, antennae 11-segmented with a club of 3 segments, 
PF 3, 2 (4, 3 in one Tranopelta species). Apart from this Ochetomyrmex species tend to have 
weakly developed frontal carinae present and the type-species (O. semipolitus Mayr) has a fine 
sharp median clypeal carina. Females and males, though less well known, are also very similar 
and have the postpetiole extremely broadly attached to the gaster. Differences separating 
Tranopelta and Ochetomyrmex are documented in Kempf (1975). 

With the exclusion of the genera discussed above the remainder of Ettershank's (1966) three 
groups appears more uniform, linked by the characters given in the diagnosis and definition 
below. As Kempf (1974) indicated, Ettershank's characters used to delineate his groups were 
not concise enough, and too many were either inapplicable or overlapped their supposed group 
boundaries. If the diagnoses given for these groups are superimposed and characters or 
combinations of characters common to all three are set aside (e.g. antennal and club segmen- 
tation, palp segmentation, structure of clypeus, venation, pedunculate petiole), then only the 
following remain. 

Monomorium-group. The anterior tentorial pit is located close to the antennal socket and 4 
malpighian tubules are present. 

Megalomyrmex-gxoxxp. The anterior tentorial pit is located about half way between the 
antennal socket and the lateral margin. 

Solenopsis-gioup. The anterior tentorial pit is located close to the antennal socket and the 
maxillary palp is geniculate. 

The number of malpighian tubules may eventually prove to be a useful character in the 
taxonomy of this group but at present far too little information is available to make any sweeping 
pronouncements. Ettershank (1966) gives counts of 4 tubules in Monomorium (= Chelaner) and 



SOLENOPSIS GENUS-GROUP 267 

in Solenopsis, and 5 in Megalomyrmex, but in the last the count is based on only a couple of 
species. Tubule counts otherwise remain unknown and it is possible that a count of 5 may be 
diagnostic of Megalomyrmex alone within the group as presently defined. 

The position of the anterior tentorial pit relative to the antennal socket is inconsistent in the 
Megalomyrmex-group as defined by Ettershank, being no further from the socket in Nothidris 
than in many Australian Monomorium from the groups which formerly constituted Chelaner. In 
both the Solenopsis- and Monomorium-groups the anterior tentorial pit also shows notable 
variation in position. Kempf (1974) observed that the pits were closer to the sockets in 
Solenopsis then in Oxyepoecus and the present survey has shown that in Anillomyrma and some 
groups of Monomorium (fossulatum-group, hanneli-group) the anterior tentorial pit is as far or 
even farther from the antennal socket than in Megalomyrmex and its supposed allies. It is 
interesting to note that in Oxyepoecus, Anillomyrma and both Monomorium species-groups 
mentioned, that the frontal lobes and antennal insertions are raised up and closely approxi- 
mated. I speculate that their migration towards the cephalic midline, whilst the position of the 
anterior tentorial pits has remained static, has brought them to a position paralleling that 
exhibited by Megalomyrmex . Whether this is the case or not , the use of the pit's position relative 
to the antennal socket as a group-diagnostic character is compromised to the point of useless- 
ness. 

Finally the geniculate maxillary palp, given as a diagnostic character of the Solenopsis-group, 
also occurs in Carebarella, which Ettershank none the less places in his Megalomyrmex- 
group. 

For these reasons it appears that taxonomic logic is better satisfied for the present if 
Ettershank's (1966) Monomorium-, Megalomyrmex-, and Solenopsis-groups are reunited into a 
single larger group, with the exclusion of Tranopelta and Ochetomyrmex, to be termed the 
Solenopsis-group after its oldest included genus. Changes in genus-level taxonomy from the 
earlier system may be summarized as follows. Unaffected genera are omitted from the list. 

Ettershank (1966) Present review 

Chelaner Included as synonym of Monomorium. 

Phacota (synonym of Monomorium) Reinstated as valid genus. 

Bondroitia (synonym of Diplomorium) Reinstated as valid genus. 

Syllophopsis Included as synonym of Monomorium. 

Hagioxenus Synonymized with Rhoptromyrmex by Bolton 

(1986a). 
Nothidris Divided into two genera, Nothidris plus 

Antichthonidris , by Snelling (1975). 
Tranopelta Excluded from the group. 

Brownidris Synonymized with Ochetomyrmex by Kempf 

(1975). 

The diagnosis and definition presented below seeks to isolate the 13 genera currently 
recognized as constituting the Solenopsis-group from all other ants of the subfamily Myrmici- 
nae. The characters listed in this attempt are as given and discussed, but some other taxonomic 
aspects, not used here because they are as yet known from far too few taxa to assess their 
universality or value, must be mentioned. 

Kugler (1978, 1979) has carried out detailed examinations of the sting structure of a number of 
myrmicine genera. These tend to a large extent to support Ettershank's (1966) exclusions from 
the group, mentioned above, and to support the groupings initiated here. But Kugler 's studies 
have generated their own problems in that genera such as Calyptomyrmex Emery, Rogeria 
Emery, and Wasmannia Forel appear close to Solenopsis and Monomorium in sting structure. 
Calyptomyrmex is very different from the Solenopsis-group in other aspects of its morphology 
(Bolton, 1981a), and the resemblances in sting mechanism are almost certainly due to converg- 
ence. Rogeria and Wasmannia are less well known. Most probably they also represent 
convergencies but more material needs to be examined before their relationships can be 



268 B. BOLTON 

accurately ascertained. On the strength of the characters listed below both genera are excluded 
from the Solenopsis-group. 

Investigations of venom chemistry carried out by Murray Blum and others indicates that the 
venoms of Solenopsis-group species, as defined here, may provide a useful character in isolating 
the genus-group. Very few species have been analysed so far, and those which have been 
examined are restricted to a few species-groups of Monomorium and Solenopsis. Nevertheless it 
appears that with the exception of the Monomorium destructor-group (Blum et al., 1985) 
alkaloids constitute a significant fraction in Solenopsis-group venoms. Moreover this is the only 
genus-group of the Myrmicinae where alkaloids have so far been detected. A good synopsis of 
the current state of knowledge of ant venom chemistry is given by Blum (1985). 

Larval characters at present are relatively little known and appear to be very confused and of 
small value as they now stand. Ettershank (1966) attempted to tabulate the main larval 
characters as they applied to his concepts, but a later synopsis by Wheeler & Wheeler (1976) 
does nothing to improve our definition of the group. In fact this last paper maintains the old 
Emery (1922) classification and a more recent synoptic classification of ant genera by Wheeler & 
Wheeler (1985) indicates that their idea of a tribe Solenopsidini remains firmly at a pre- 
Ettershank level. They include many genera now certainly known to have affinities well away 
from the groups envisaged by Ettershank (1966) or accepted here. Larval characters will 
probably hold some interesting clues about the generic and suprageneric classification of the 
Myrmicinae, but until the characters are re-assessed in the light of modern taxonomic opinion 
they will remain of little use. 

The karyology of myrmicine ants is presently little known, very few species having been 
investigated. For this reason the effects of karyological studies at levels above the species cannot 
yet be ascertained with any hope of meaningful conclusions being drawn. In Monomorium and 
Solenopsis indications are however promising, as surveys to the present seem to indicate that 
karyotypes may provide an additional character for discrimination at the species-group level 
(Crozier, 1970; Imai etal., 1984). 

Thus the overall effect of recent taxonomic work has been to restrict and condense the 
Solenopsis-group by synonymy of genus-level names originally appearing distinct but rendered 
untenable because of more recent collections which bridge the supposed gaps between them, by 
closer definition of the known genera, and by exclusion of genera not certainly related. Whilst it 
is definitely not claimed that the last taxonomic word on the subject of the Solenopsis-group has 
been spoken, it is hoped that at least some of the outstanding taxonomic inconsistencies have 
been dealt with. 

Measurements and indices 

Total Length (TL). The total outstretched length of the ant from the mandibular apex to the 
gastral apex. 

Head Length (HL). The length of the head proper, excluding the mandibles, measured in a 
straight line from the mid-point of the anterior clypeal margin to the mid-point of the occipital 
margin, in full-face view, ignoring any projecting teeth which may be present on the clypeus. 
In species where the occipital margin or the clypeal margin (or both) is concave the 
measurement is taken from the mid-point of a transverse line spanning the anteriormost or 
posteriormost projecting points respectively. 

Head Width (HW) . The maximum width of the head in full-face view , measured behind the eyes . 

Cephalic Index (CI) . HW x 1Q0 

HL 

Scape Length (SL). The maximum straight line length of the antennal scape excluding the basal 
constriction or neck close to the condylar bulb. 

Scape Index (SI) . SL x 10 ° 

HW 



SOLENOPSIS GENUS-GROUP 269 

Pronotal Width (PW). The maximum width of the pronotum in dorsal view. 
Alitrunk Length (AL). The diagonal length of the alitrunk in profile from the point at which the 
pronotum meets the cervical shield to the posterior base of the metapleuron. 

Depositories 

ANIC Australian National Insect Collection, C.S.I.R.O., Canberra City, Australia. 

BMNH British Museum (Natural History), London, U.K. 

CdF Musee d'Histoire Naturelle, La Chaux-de-Fonds, Switzerland. 

EUU Entomology Department, University of Uppsala, Uppsala, Sweden. 

MCSN Museo Civico di Storia Naturale 'Giacomo Doria', Genoa, Italy. 

MCSNV Museo Civico di Storia Naturale di Verona, Italy. 

MCZ Museum of Comparative Zoology, Cambridge, Mass., U.S.A. 

MHN Museum d'Histoire Naturelle, Geneva, Switzerland. 

MNHN Museum National d'Histoire Naturelle, Paris, France. 

MNHU Museum fur Naturkunde an der Humboldt-Universitat zu Berlin, Germany (D.D.R.). 

MRAC Musee Royal de l'Afrique Centrale, Tervuren, Belgium. 

NMB Naturhistorisches Museum, Basel, Switzerland. 

NMV Naturhistorisches Museum, Vienna, Austria. 

SAM South African Museum, Cape Town, South Africa. 

UM University Museum, Oxford, U.K. 

The SOLENOPSIS-group 

Diagnosis. Myrmicine ants with the following combination of characters. 

(1) Masticatory margin of mandible with 5 or fewer teeth (one species-group forming a derived exception, 
see definition below). 

(2) Median clypeal seta present, clearly differentiated and conspicuous (secondarily lacking only in some 
Solenopsis males). 

(3) Clypeus lacking a median longitudinal ridge or carina. 

(4) Lateral portions of clypeus not modified into raised ridges or prominent plates. 

(5) Frontal lobes not extending posteriorly as frontal carinae. 

(6) Antennal scrobes absent. 

(7) Antennae in worker and female never 12-segmented with a 2-segmented club. 

(8) Tibial spurs of middle and hind legs not pectinate. 

(9) Metapleural lobes (=inferior propodeal plates) never elongate triangular and never acute. 

(10) Petiole pedunculate anteriorly and with a distinct node; peduncle never with an enormously 
developed anteroventral process. 

(11) Petiolar spiracle in worker and female not in front of midlength of the peduncle. 

(12) Cross-vein r-m absent from forewing (except in a few Solenopsis males). 

(13) Radial (=marginal) cell of forewing open distally. 

Definition. Workers and females . Myrmicine ants with PF 5, 3 or less. PF 2, 2 is predominant; maxillary 
palp with 5 segments only in two Malagasy Monomorium, maxillary palp 4-segmented only in Nothidris 
and the Megalomyrmex goeldii-group, fewer everywhere else. Masticatory margin of mandible with 5 or 
fewer teeth (usually 4), apical tooth the largest, the remainder decreasing in size towards the base. 
(Mandibles with only apical tooth in inquiline female of Monomorium hospitum Viehmeyer; teeth reduced 
to two in inquiline females of M. inquilinum DuBois, M. talbotae DuBois and Antichthonidris bidentata 
(Mayr). In the Megalomyrmex modestus-group usually the proximal portion of the mandible showing a 
proliferation of minute denticles between or instead of the main teeth.) Median clypeal seta present, 
usually long and conspicuous. Clypeus lacking a median longitudinal ridge or carina; median portion of 
clypeus frequently bicarinate but always lacking multiple longitudinal rugae or carinae. Lateral portions of 
clypeus not forming a raised rim or shield wall in front of the antennal insertions, nor reduced to prominent 
anteriorly projecting plates. Frontal carinae absent behind level of frontal lobes and antennal scrobes 
never developed. Frontal lobes small and narrow, usually only partially concealing the antennal insertions 
in full-face view (in workers, rarely larger in females). Antennae with 7-12 segments but if 12 then the 
apical club is never of 2 segments. Sculpture of head fine and dense to absent, never of coarse rugosity, 
never reticulate-rugose. Promesonotum unarmed in workers, lacking teeth, spines or tubercles; pronotum 
and mesonotum unarmed in females. Mesothoracic spiracles not opening onto dorsal alitrunk. Propodeum 



270 B. BOLTON 

almost universally unarmed, sometimes (Oxyepoecus, Nothidris, some Monomorium) sharply angulate or 
with projecting subtriangular lamellae or denticles; distinct propodeal spines are present only in Antichtho- 
nidris bidentata, a few aberrant Australian Monomorium, workers of Allomerus vogeli Kempf, and one or 
two apterous females of Monomorium salomonis-group. Propodeal spiracle at or close to the propodeal 
midlength, not shifted posteroventrally except in a very few Australian Monomorium; the spiracle grossly 
enlarged in Bondroitia. Metasternal process vestigial to absent; ventral alitrunk lacking an elongate 
A -shaped cleft running from the posterior margin between the hind coxae. Metapleural lobes variously 
shaped but usually small and rounded, sometimes reduced to vestigial lamellar strips but never elongate- 
triangular with an acute apex. Hind tibiae with spurs simple to absent, not pectinate. Forewing (alate 
female) with radial cell open, vein Rs not curving towards the leading edge of the wing to fuse with the 
marginal abscissa of R distal of the pterostigma. Forewing with cross-vein r-m absent. Petiole pedunculate 
and with a differentiated unarmed node which in workers is usually subconical in profile, but sometimes 
otherwise. Subpetiolar process small to absent; petiole and postpetiole lacking spongiform appendages. 
Petiolar spiracle at or (usually) behind the midlength of the peduncle, not close to the articulation of 
peduncle with alitrunk. Promesonotum (workers) with sculpture fine and dense to absent; propodeum 
similar or with stronger sculpture than the foregoing. Alitrunk never adorned with multiple peaks or 
tubercles. Pilosity simple when present. 

Males. As above but with the following modifications. 

Masticatory margin of mandibles often as above but frequently with only two teeth. In Carebarella the 
mandibles are atrophied and in some groups of Monomorium and elsewhere the male mandible has fewer 
teeth than the conspecific worker or female, sometimes only the apical tooth is developed. Median portion 
of clypeus not longitudinally bicarinate. Median clypeal seta usually conspicuous but variously developed 
in Solenopsis and sometimes absent. Frontal lobes minute to absent, never covering the antennal 
insertions. Antennae with 12 or 13 segments, not clavate apically. First funicular segment frequently 
reduced, sometimes globular; funiculus basally lacking elongate fusion segments. Mesoscutum generally 
lacking notauli, present only in some Australian Monomorium and in the South American Antichthonidris . 
Mesoscutellum unarmed posteriorly. Propodeum unarmed and not grossly reduced with respect to the 
mesothorax. Propodeal spiracle in front of midlength of side. Node of petiole often reduced and more 
rounded than in worker or female. Venation characters as in alate female but very rarely Solenopsis males 
may be found in which cross-vein r-m is still visible. Sculpture varying from dense and quite coarse to 
absent, frequently the male more strongly sculptured than the conspecific female or worker. 

The diagnosis above is an attempt to separate all 13 genera of the Solenopsis-group from the rest of the 
Myrmicinae. Thus any myrmicine species not showing all these characters in combination and failing to 
conform to the definition is excluded from the group. 

It must be admitted that whilst the above characters are reasonable for workers and females their 
universality in males cannot be assessed in great detail at present as males are known for relatively few 
species in the genus-group as a whole, and remain unknown or known for only a single species in some 
genera. 

The phylogenetic significance of the characters can be partially assessed. Using the A/yrm/ca-group and 
Tetramorium-group as outgroups for comparison, as they reflect most characters currently considered to 
approximate the ancestral myrmicine condition, the characters enumerated above segregate as follows. 
Characters (1), (3), (8), (12), and (13) are apomorphic by reduction. The corresponding plesiomorphic 
states are (1) mandibles serially multidentate; (3) median longitudinal ridge or carina conspicuous on 
clypeus: (8) tibial spurs pectinate; (12) cross-vein r-m present; (13) radial cell closed. Character (2) is 
apomorphic by development. The plesiomorphic state here is envisaged as a continuous row of undiffe- 
rentiated clypeal setae, without an obvious median component. Characters (4), (5), and (6) are plesiomor- 
phic as stated but are useful as taxonomic diagnostics, serving to exclude all taxa with modified lateral 
clypeal structure, frontal carinae, or antennal scrobes. 

Structure of the antennae in workers and females, character (7), shows much variation in the 
Solenopsis-group. However, the combination of 12-segmented antennae with a 2-segmented club does not 
occur and is listed here to exclude the otherwise close genera Adelomyrmex Emery and Baracidris Bolton. 
It seems most likely that this antennal structure is an apomorphy peculiar to each of these genera, but it 
may not be synapomorphic between them. Characters (9), (10), and (11) are difficult to interpret in terms 
of polarity. In the case of character (10) it seems apparent that a sessile petiole is the ancestral 
(plesiomorphic) state as it is shown in the ectatommine ponerines, which constitute the sister-group of the 
entire Myrmicinae. However, the myrmicine groups which correspond most closely to the ectatommines, 
the My mr/ca-group and Tetramorium-group, show a pedunculate petiole. Evidence is ambiguous but it 



SOLENOPSIS GENUS-GROUP 271 

must be considered possible that some or all myrmicines which currently show a sessile petiole may in fact 
be expressing a secondary development from pedunculate ancestral forms rather than a retention of the 
plesiomorphic sessile condition exhibited by the ectatommines. 

Position of the petiolar spiracle, character (11), is usually consistent within narrow limits within 
genus-groups. Unfortunately polarity of the states is hard to assess as the petiolar peduncle may be 
developed in more than one way. In the sessile petiole the spiracle is normally at the base of the node's 
anterior face and close to the articulation with the alitrunk. Where a peduncle is developed it can be 
envisaged as an elongation of the section in front of the spiracle, or the section behind it, or both. In the first 
case the spiracle would be 'left behind', remaining close to the node as the peduncle opened a gap between 
node and anterior articulation. In the second case the developing peduncle would open a gap between the 
spiracle and the node, leaving the former close to the anterior articulation whilst the node was shifted 
posteriorly. Both mechanisms acting at once, or a later migration by the spiracle from either of these 
conjectural original positions, would leave the spiracle in an intermediate position. Obviously more study 
of both characters (10) and (11) is required throughout the Myrmicinae before any conclusions can be 
drawn. 

Thirteen genera are currently recognised in the Solenopsis-group. As a group they show world-wide 
distribution but the vast majority of species are confined to the tropics and subtropics. 

Investigation of the phylogenetic relationships of these 13 genera is in its infancy. At present complexes 
of genera appear best associated by the following series of characters, displayed by the female and worker 
castes (males are not well enough known). Polarity of many of these characters remains to be determined. 
Anillomyrma + Bondroitia: fore coxae greatly enlarged; mandibular apices cross over; eyes absent; 
subpetiolar process lost; promesonotum uniformly flat. Versus in the remaining 11 genera: fore coxae not 
enlarged; mandibular apices overlap; eyes present; subpetiolar process present; promesonotum convex at 
least in part. 

Solenopsis + Oxyepoecus + Carebarella: maxillary palp geniculate (after Ettershank (1966); the univer- 
sality of this character remains to be investigated in detail). Versus in the remaining 8 genera: maxillary 
palp not geniculate. 

Allomerus + Diplomorium: median clypeus broad and shield-like; median clypeus not bicarinate; anten- 
nal insertions widely separated; antennal club segments specialized. Versus in the remaining 6 genera: 
median clypeus relatively narrow; median clypeus bicarinate (some with carinae secondarily partially or 
totally lost); antennal insertions relatively close together; antennal club segments not specialized. 
Epelysidris: basal border of mandible bilobate. Versus in the remaining 5 genera: basal border of mandible 
unarmed. 

Monomorium + Nothidris + Phacota + Megalomyrmex + Antichthonidris. It is possible that Phacota (see 
there) represents nothing more than an ergatoid female of the Monomorium salomonis-group. I am not 
sure that Nothidris and Antichthonidris represent anything more than a southern Neotropical fraction of 
the Australasian Monomorium fauna, and Megalomyrmex remains to a large extent insufficiently defined. 
Much more information on the Australasian and Neotropical faunas will be necessary before any 
conclusions can be drawn. 

Key to Solenopsis-group genera (workers) 

The key is based on workers as females and males are insufficiently known, or in some genera remain 
unknown. Monomorium, Allomerus and Megalomyrmex, which show variation in antennal segment 
count, palp formula, or both, are keyed out in more than one position. 

1 Antennae with 7-10 segments 2 

— Antennae with 1 1-12 segments 6 

2 Eyes absent. Postpetiole articulated high on the first gastral tergite (Figs 1, 4). (Oriental and 

Indo-Australian) ANILLOMYRMA (p. 273) 

— Eyes present. Postpetiole articulation normal , not high on the first gastral tergite 3 

3 Antennal club of 2 segments. Maxillary palp geniculate . Antennae always with 10 segments 4 

— Antennal club of 3 segments. Maxillary palp not geniculate . Antennae with 7-10 segments 5 

4 Median portion of clypeus abruptly raised and flat-topped, the raised platform bounded by the 

parallel paired clypeal carinae which then turn mesad anteriorly and meet anteromedially to 
form the anterior margin of the raised portion. (Neotropical) CAREBARELLA (p. 286) 

— Median portion of clypeus without a raised flat-topped section, instead the two clypeal carinae 

divergent anteriorly and running to the margin where they often project as a pair of teeth or 
denticles. Clypeal carinae never turning mesad anteriorly nor meeting anteromedially. 
(Worldwide) SOLENOPSIS (p. 285) 



272 B. BOLTON 

5 Palp formula 3, 2. Median portion of clypeus evenly transversely convex, not longitudinally 

bicarinate. Antennal club segments each constricted basally. (Neotropical) 

ALLOMERUS (part, p. 282) 

— Palp formula 2,2 or 1,2. Median portion of clypeus raised and longitudinally bicarinate. 

Antennal club segments not constricted basally. (Australia) MONOMORIUM (part, p. 287) 

6 Antennae with 1 1 segments 7 

— Antennae with 12 segments 12 

7 Eyes absent. Propodeal spiracle enormously enlarged (Figs 2, 5). (Afrotropical) 

BONDROITIA (p. 275) 

— Eyes present. Propodeal spiracle not enormously enlarged 8 

8 Antennal club of 2 segments. Head almost circular in full-face view, the eyes behind the 

midlengthofthe sides of the head. (Spain) PHACOTA(p. 281) 

— Antennal club of 3 segments. Head not circular in full-face view, the eyes in front of the 

midlength of the sides of the head 9 

9 Propodeum in profile sharply angulate to bidentate between dorsum and declivity 10 

— Propodeum in profile unarmed , the dorsum curving evenly into the declivity 11 

10 Median portion of clypeus sharply longitudinally bicarinate , the carinae terminating in a pair of 

projecting teeth. Mandibles with 4 teeth. PF 2,2. Segments of antennal club not constricted 
basally. (Neotropical) OXYEPOECUS{p. 286) 

— Median portion of clypeus evenly convex, not longitudinally bicarinate and lacking a pair of 

projecting teeth. Mandibles with 5 teeth. PF 3,2. Segments of antennal club distinctly 
constricted basally. (Neotropical) ALLOMERUS (part, p. 282) 

11 Median portion of clypeus distinctly raised, strongly to weakly longitudinally bicarinate. 

Postpetiole node less voluminous than petiole node in profile and narrowly attached to 
gaster. (Widespread in Old World) MONOMORIUM (part, p. 287) 

— Median portion of clypeus evenly transversely convex, not distinctly raised nor longitudinally 

bicarinate. Postpetiole node much more voluminous than petiole node in profile and very 
broadly attached to gaster (Figs 3,6). (South Africa) DIPLOMORIUM(p. 278) 

12 Basal border of mandible with two posteriorly directed broad rounded lobes, the first close to 

the basalmost of the 5 teeth, the second near the trulleum (Fig. 17). (Borneo) 

EPELYSIDRIS(p. 279) 

— Basal border of mandible without posteriorly directed lobes 13 

13 Maxillary palp with 4-5 segments 14 

— Maxillary palp with 1-3 segments 16 

14 Maxillary palp with 5 segments. (Madagascar) MONOMORIUM (part, p. 287) 

— Maxillary palp with 4 segments. (Neotropical) 15 

15 Propodeal declivity with a transversely arched rim or carina running between the uppermost 

points of the metapleural lobes. Propodeal spiracle not preceded on side of alitrunk by a 
thin-walled vestibule which is conspicuous through the cuticle. (Neotropical) 

MEGALOMYRMEX (part, p. 285) 

— Propodeal declivity without an arched rim or carina between the uppermost points of the 

metapleural lobes. Propodeal spiracle preceded on side of alitrunk by a thin-walled vestibule 
which is conspicuous through the cuticle . (Chile) NOTMDRIS{p. 284) 

16 Palp formula 3,2. Mandibular dentition irregular behind the preapical tooth, either with 

numerous minute denticles or with regular teeth interspersed with minute denticles. 
(Neotropical) MEGALOMYRMEX (part, p. 285) 

— Palp formula never 3,2; variable but usually 2,2. Either mandibular teeth regularly decreasing 

in size from apex to base or with basal tooth reduced, not irregular as above and with 3-5 
teeth in all 17 

17 Mandible with 5 teeth. Palp formula 2,2. Anterior tentorial pit midway between antennal 

socket and lateral margin of clypeus. Propodeum bidentate to bispinose. (Chile & southern 
Argentina) ANTICHTHONIDRIS (p. 283) 

— Mandible with 3-5 teeth, usually with 4. If 5 teeth present then either palp formula not 2,2, or 

anterior tentorial pit close to antennal socket, or propodeum unarmed, or all of these 
together. (Worldwide) MONOMORIUM (part, p. 287) 



SOLENOPSIS GENUS-GROUP 273 

ANILLOMYRMA Emery 

(Figs 1,4) 

Anillomyrma Emery, 1913: 261 [as subgenus of Monomorium]. Type-species: Monomorium decamerum 

Emery, 1901: 117; by monotypy. 
Anillomyrma Emery; Ettershank, 1966: 97. [Raised to genus.] 

Worker. Minute (TL<2-0) monomorphic subterranean myrmicine ants. PF 2,1, the labial palpomere 
composed of two semi-fused segments, the apical half of which is flattened and lobiform so that the labial 
palp is much larger than the two-segmented subcylindrical maxillary palp. Mandibles with 3-4 teeth, the 
masticatory margins very oblique and the mandibular apices crossing over at full closure. Trulleum small 
and closed. Eyes absent. Antennae 10-segmented with a very large 3-segmented apical club. Funicular 
segments 2-6 reduced to very short broad annuli. Frontal lobes very closely approximated, the posterior 
portion of the clypeus which passes between them very narrow, narrower than the width of either lobe. 
Median portion of clypeus narrow and distinctly raised above the level of the lateral portions, the median 
portion narrowly transversely convex and lacking longitudinal carinae. Promesonotum flat dorsally, the 
metanotal groove represented by a straight line across the dorsum, not impressed. Fore coxae much 
enlarged, very much larger than the middle and hind coxae. Propodeal spiracle small, its orifice circular and 
situated at about the midlength of the sclerite. Petiole with a long anterior peduncle, lacking an 
anteroventral process. Petiole node long, low and dorsally broadly convex in profile. Postpetiole low and 
small in profile, in dorsal view very broadly attached to the gaster. In profile the postpetiole articulated high 
on the first gastral segment. Sting large and strongly sclerotized, disproportionately powerful. 

Female and Male. Unknown. 

This distinctive small genus contains only two species and one subspecies, the last probably synonymous 
with the type-species of the genus. As Wheeler (19276) suggested, Anillomyrma is most closely related to 
Bondroitia, sharing characters of mandibular structure, lack of eyes, close approximation of frontal lobes 
and antennal insertions, very narrow median clypeus which lacks longitudinal carinae, enlarged fore 
coxae, and conspicuously flattened promesonotal dorsum. Habitus of the two genera is also similar, 
compare Figs 1, 2, 4, 5. Anillomyrma and Bondroitia together separate from the remainder of the 
Solenopsis-group by their joint possession of strongly crossing mandibular blades, lack of eyes, flattening 
of the alitrunk dorsum, lack of clypeal carinae on median portion of clypeus (Diplomorium and some 
Neotropical taxa lack carinae but here the clypeus is broad), very closely approximated frontal lobes 
(similar in the Monomorium fossulatum-group) , lack of a subpetiolar process, and enlarging of the fore 
coxae. 

The two genera are separated by the following characters in the worker. 
Anillomyrma (Figs 1 , 4) Bondroitia (Figs 2, 5) 

(1) Antennae 10-segmented. Antennae 11-segmented. 

(2) Palp formula 2,1. Palp formula 2,2. 

(3) Labial palpomere expanded, flattened and Labial palpomeres cylindrical to subcylindrical. 
lobate. 

(4) Propodeal spiracle small, at about the Propodeal spiracle enormous, behind the 
midlength of the sclerite . midlength of the sclerite . 

(5) Metanotal groove not impressed on the Metanotal groove impressed on the dorsum, 
dorsum. 

(6) Metapleural glands conspicuous. Metapleural glands very small. 

(7) Postpetiole attached high on the first gastral Postpetiole attached to the gaster in normal 
segment. position. 

(8) Postpetiole-gaster articulation very broad. Postpetiole-gaster articulation narrow. 

(9) Sting relatively very large and powerfully Sting relatively small and feeble, 
developed. 

It is possible that some similarities of Anillomyrma and Bondroitia are superficial and due to morpho- 
logical convergence through the similarity of their lifeways. In particular this may apply to their loss of 
eyes and the flattening of the dorsal alitrunk. However, the form of the mandibles, the narrowing of the 
median clypeus with close approximation of the frontal lobes, the disappearance of the subpetiolar process 
and the increase in size of the fore coxae appear to be valid synapomorphies isolating these two genera from 
the remainder of the genus-group. 

Accepting that Anillomyrma and Bondroitia together form a holophyletic grade within the Solenopsis- 



274 B. BOLTON 

group on the strength of the characters just mentioned, then of the nine characters tabulated to separate 
the two genera those apomorphic in Anillomyrma are (1), (2) and (5) by reduction and (3), (7) and (8) by 
development; whilst those apomorphic in Bondroitia are (6) and (9) by reduction and (4) by development, 
as compared to the remainder of the genus-group. 

Very little is known of the biology of this genus. The few samples of decamera which are known were 
taken in soil or litter samples, or from termite nests, the occupants of which may or may not constitute the 
normal prey of the species. A. tridens was discovered in Sarawak crossing a small forest path by means of a 
covered runway in the topsoil. The runway was very conspicuous where it crossed the path and consisted of 
a narrow shallow groove in the soil which was covered by a canopy of small soil particles, concealing the 
ants moving along inside the tube thus formed. On disturbing the soil of the runway large numbers of 
minute yellowish ants poured out to investigate. Handling these tiny ants proved to be a mistake as they use 
their stings freely and, though minute, they are capable of penetrating the skin and delivering a painful 
sting out of all proportion to the size of the ant. The ant runway was revisited a few hours later and workers 
were still moving along within though no trace of sexuals or brood could be found. 

I am unable to say whether this movement represented a nest transfer or whether A. tridens is nomadic, 
but the ant runway was not on the forest path the day before its discovery and was deserted the day after, 
and shortly after that was washed away by a downpour. The site of the runway was checked periodically for 
the next couple of weeks but the ants never returned. 

Key to species (workers) 

1 Mandible with 3 teeth, consisting of a large apical and preapical tooth which are close together, 

followed by a diastema and a large third (basal) tooth. (East Malaysia: Sarawak) tridens(p. 274) 
— Mandible with 4 teeth , consisting of a large apical and preapical tooth which are close together, 
followed by a diastema and a large third tooth, basal to which is a distinctly smaller fourth 
tooth. (Sri Lanka, India, Vietnam) decamera(p. 21 A) 

Anillomyrma decamera (Emery) 

Monomorium decamerum Emery, 1901: 117. Syntype workers, Sri Lanka: Anuradhapura, in Ter- 

mitennestern, 1899 (W. Horn) (MCSN) [not seen]. 
Monomorium (Anillomyrma) decamerum Emery; Emery, 1913: 261. 
Anillomyrma decamera (Emery); Ettershank, 1966: 98. 

A. decamera is characterized within the genus, and separated from tridens, by its 4-dentate mandibles. 
Wheeler (19276) described a subspecies continentis from Van Phu (? Vietnam), but from the description 
this seems indistinguishable from Indian specimens of decamera deposited in BMNH . I suspect that further 
investigation will show continentis to be a synonym of decamera. 

Material examined 
India: Bihar, Ranchi Dist., Ormanjai (P. B. Sinha). 

Anillomyrma tridens sp. n. 

(Figs 1,4) 

Holotype worker. TL 1-8, HL 0-38, HW 034, CI 89, SL 0-22, SI 58, PW 0-24, AL 0-38. 

With habitus as in Figs 1,4, and with characters of generic diagnosis. Mandibles with three large sharp 
teeth, which are darker in colour than the remainder of the body. Apical and preapical teeth close together, 
separated by a diastema from the third (basal) tooth, the third tooth shallowly curved towards the apex of 
the mandible. Antennal scapes short (SI 60 or less), slightly shorter than the funiculus which measures ca 
0-36 in the holotype. Of the funicular segments the first is ca 0-06, the annular segments 2-6 measure only 
0-06 together, and the relatively large club is 0-24 (the club is longer than the scape). Pronotal humeri very 
broadly rounded in dorsal view, the dorsal alitrunk pinched in at the metanotal line. Petiole node longer 
than broad in dorsal view, the postpetiole slightly broader than long. All dorsal surfaces of head and body 
with abundant short soft fine standing hairs; the legs, scapes and sides of head with similar hairs which 
project freely. Sculpture absent except for hair-pits, which are most conspicuous on the head and 
pronotum. Colour very pale yellowish white, extensively depigmented. 

Paratype workers. TL 1-8-1-9, HL 0-37-0-39, HW 0-33-0-36, CI 88-90, SL 0-21-0.23, SI 57-60, PW 
0-24-0.25, AL 0-35-0-39 (10 measured). As holotype. 



SOLENOPSIS GENUS-GROUP 275 

Holotype worker, East Malaysia: Sarawak, 4th. Division, Gunong Mulu Nat. Park, RGS Expd., Long 
Pala, 11.x. 1977, lowland rain forest in sandy soil (B. Bolton) (BMNH). 

Paratypes. 39 mounted workers plus many more in alcohol, with same data as holotype (BMNH; MCZ; 
MHN; NMB). 

BONDROITIA Forel gen. rev., stat. n. 

(Figs 2, 5, 7-11) 

Bondroitia Forel, 1911a: 300 [as subgenus of Monomorium]. Type-species: Monomorium (Martia) coecum 

Forel, 1911a: 299 (= Diplomorium lujae Forel, 1909: 72); by monotypy. 
Bondroitia Forel; Ettershank, 1966: 98 [as synonym of Diplomorium]. 

Note. The first appearance in the literature of the name Bondroitia occurs in Forel (1911a) where, at the 
end of his discussion of Monomorium coecum, he says, 'Perhaps subsequent knowledge of the female and 
male would justify the erection of a new subgenus, for which I would then take the liberty of proposing the 
name Bondroitia.'' As this conditional statement was made as early as 1911, and as it follows a detailed 
description of M. coecum worker, the name Bondroitia is available under the articles of the International 
Code of Zoological Nomenclature , from the date of that publication. Thus the first valid publication of the 
name Bondroitia is Forel (1911a: 300), with the type-species Monomorium coecum Forel, by monotypy. 
The slightly later description of Bondroitia as a subgenus of Diplomorium, by Forel (19116: 398, with D. 
lujae given as type-species), where Bondroitia was referred to as a 'new subgenus', is invalid and should be 
discarded. 

Worker. Monomorphic myrmicine ants with noticable size-variation in any series but not exhibiting 
allometric variation (Figs 2, 5). PF 2,2, the palpomeres subcylindrical (lujae). Mandibles with 4 teeth 
arranged on a markedly oblique masticatory margin, the blades crossing over at full closure. Trulleum 
small and closed. Eyes absent. Antennae 11-segmented with a 3-segmented apical club. Frontal lobes 
closely approximated, the posterior portion of the clypeus where it passes between them narrow, only 
about as wide as one of the frontal lobes or slightly narrower. Median portion of clypeus narrowly 
transversely convex posteriorly, shallowly concave anteriorly, especially in larger workers. Clypeus 
without longitudinal carinae. Promesonotum flat dorsally. Metanotal groove impressed on dorsal alitrunk. 
Metapleural glands small and inconspicuous. Fore coxae enormously enlarged by comparison to mid and 
hind coxae. Propodeal spiracle enormous, very close to margin of declivity and low on the side, its orifice 
circular and behind the midlength of the sclerite . Petiole nodiform in profile , the anterior peduncle lacking 
a ventral process. Postpetiole small, conspicuously less voluminous than the petiole in profile. Postpetiole 
in dorsal and lateral view narrowly attached to gaster, not articulating high on the first gastral segment. 
Sting small and inconspicuous. (Diagnosis based on lujae, worker of saharensis is unknown). 

Female. Enormously larger than conspecific worker, head relatively very small in comparison to body size. 
PF 2,2 (lujae, saharensis). Mandible with 3 teeth, the blade narrow and with a markedly oblique 
masticatory margin (Fig. 7) . Anterior clypeal margin unarmed , evenly shallowly convex and not overhang- 
ing the mandibles. Median portion of clypeus evenly transversely convex, not raised nor bicarinate. 
Clypeus posteriorly broadly inserted between frontal lobes, the outer margins of the latter constricted 
behind, with a pinched-in appearance behind the lobes themselves. Eyes large and close to midlength of 
sides of head. Antennae 11-segmented, the club weakly 4-segmented, not strongly defined but rather the 
antennomeres gradually increasing in size apically. Mesothoracic axillae small, subtriangular and widely 
separated on the dorsum (Fig. 9). Mesoscutum and scutellum fitting tightly together, not separated by a 
broad impression. Metapleural glands small and inconspicuous. Venation of forewing as Fig. 11, with 
cross-vein m-cu present. Peduncle of petiole lacking an anteroventral process. In profile the postpetiolar 
sternite a very small sclerite. In dorsal view the postpetiole subglobular and only narrowly attached to the 
gaster. 

Male. Enormously larger than the conspecific worker but smaller than the female. Head very small by 
comparison with remainder of body (Fig. 10). Mandibles bidentate. PF 2,2 (lujae, saharensis). Antennae 
with 12 segments (lujae) or 13 segments (saharensis), if 12 then the apical is an elongate fusion-segment. 
First funicular segment globular, only about half the length of either the scape or the second funicular 
segment. Funiculus from segment 2 to apex gradually tapering, not whip-like. Eyes large, at about the 
midlength (lujae) or extended anteriorly and reaching the clypeus (saharensis). Head not strongly 
produced backwards behind the eyes. Notauli absent. Parapsidal grooves present but faint. Axillae small 



276 



B. BOLTON 



and widely separated. Mesoscutum and scutellum separated only by a narrow slit between the axillae, 
without a broad impressed groove. Propodeal spiracle very large and circular. Venation as in female. 
Peduncle of petiole without an anteroventral process . Postpetiolar sternite small in profile , the tergite large 
and very broadly attached to the gaster. 

Ettershank (1966) treated Bondroitia as a synonym of Diplomorium where previously it had been usual 
to regard it as a subgenus, following Emery (1922). Only rarely was Bondroitia regarded as a valid genus 
(Wheeler, 1922) but the present analysis concludes that Bondroitia must stand as a genus apart from 
Diplomorium. As presently constructed the genus contains only two species, lujae and saharensis. For 
other disposals from Diplomorium in the sense of Ettershank (1966), see under Diplomorium. 

Workers and females of the two genera separate on the following suite of characters; the male of 
Diplomorium remains unknown. 



Diplomorium 

Workers (Figs 3, 6) 

Masticatory margin of mandible not markedly 

oblique; blades overlap but do not cross over at 

full closure. 
Clypeus very broad between frontal lobes, 

antennal insertions widely separated (width 

across frontal lobes at maximum 

separation = 0.48 times width of head at that 

level). 
Extreme lateral portion of clypeus not dentate 

over outer border of mandible. 

Eyes present. 

First segment of antennal club (funiculus segment 

8) very much smaller than second club segment 

(funiculus segment 9). 
Promesonotum convex. 
Fore coxae not much larger than the middle and 

hind coxae. 
Propodeal spiracle small, situated approximately 

at midlength of propodeal side. 
Metapleural glands large. 
Peduncle of petiole with an anteroventral process. 



Females (Figs 12-15). 

Mandibles with 4-5 teeth. 

Anterior clypeal margin projecting as a broad 

triangle medially, extensively overhanging the 

mandibles. 
Frontal lobes evenly convex, not pinched in 

posteriorly behind the antennal insertions. 

Antennae with a strongly defined 3-segmented 

club. 
Axillae joined across mesothoracic dorsum by a 

broad shallow groove which separates the 

mesoscutum and scutellum. 
Metapleural glands large. 
Peduncle of petiole with a conspicuous 

anteroventral process. 
Postpetiolar sternite large in profile. 
Postpetiole in dorsal view transverse and very 

broadly attached to the gaster. 



Bondroitia 
Workers (Figs 2, 5) 

Masticatory margin of mandible markedly oblique; 
blades crossing over at full closure. 

Clypeus very narrow between frontal lobes, 

antennal insertions closely approximated (width 

across frontal lobes at maximum 

separation = 0-30 times width of head at that 

level). 
Extreme lateral portion of clypeus projecting as a 

low broad triangular tooth over outer basal 

border of mandible. 
Eyes absent. 
First segment of antennal club (funiculus segment 

8) subequal in size to second club segment 

(funiculus segment 9). 
Promesonotum flat. 
Fore coxae enormously enlarged when compared 

to the middle and hind coxae. 
Propodeal spiracle enormous, situated at posterior 

margin of propodeal side. 
Metapleural glands small. 
Peduncle of petiole lacking an anteroventral 

process. 

Females (Figs 7-11). 
Mandibles with 3 teeth. 
Anterior clypeal margin evenly convex, not 
overhanging the mandibles. 

Frontal lobes convex anteriorly, concave 
posteriorly, pinched in behind the antennal 
insertions. 

Antennae with a weakly defined 4-segmented club. 

Axillae joined across mesothoracic dorsum by a 

narrow incised line, the mesoscutum and 

scutellum fitting tightly together. 
Metapleural glands small. 
Peduncle of petiole without an anteroventral 

process. 
Postpetiolar sternite small in profile. 
Postpetiole in dorsal view subglobular and only 

narrowly attached to the gaster. 



SOLENOPSIS GENUS-GROUP 277 

The real affinities of Bondroitia appear to lie with Anillomyrma. Five apparently good synapomorphies 
link the workers of the two genera and exclude Diplomorium and other members of the genus-group. 
The mandibular apices cross over at full closure. 
Median portion of clypeus is much narrowed posteriorly so that the antennal insertions are closely 

approximated. (The mechanism for this may be the approximation of the antennal insertions causing the 

narrowing of the clypeus, rather than vice versa.) 
Bicarinate nature of the clypeus is secondarily lost. 
Anterior pair of coxae are much enlarged. 
Subpetiolar process is lost from the peduncle. 

Other characters, possibly also synapomorphies but just possibly acquired convergently, include loss of 
eyes and flattening of the promesonotum. A list of apomorphic characters separating Anillomyrma and 
Bondroitia is given under the former name. The present analysis leads to the conclusion that the characters 
which have been used in the past to link Bondroitia to Diplomorium are either plesiomorphic or the result 
of convergence. This includes, in both workers and females, the low PF and dental count, the lack of a 
bicarinate clypeus (I suspect that whilst Bondroitia has certainly lost the carinae Diplomorium may never 
have had them), the 11-segmented antennae (where differences in formation of the club imply different 
developmental routes); and in females alone the venation and relative width of the clypeus between the 
frontal lobes. 
The two species included in Bondroitia are as follows. 

Bondroitia lujae (Forel) comb. n. 
(Figs 2, 5, 7-11) 

Diplomorium lujae Forel, 1909: 72. Syntype workers, females, males, Zaire: Kasai, Sankura (E. Luja) 

(MHN) [examined]. 
Monomorium (Martia) coecum Forel, 1911a: 299. Holotype worker, Switzerland: Geneva (locality in 

error) (MHN) [examined]. Syn. n. 

Characters given by Forel (19116: 397) for separating lujae and coecum have no foundation in reality. 
The mandible of coecum has 4 teeth, not 3 as stated, and the very minor differences otherwise noted are 
part of the normal variation of lujae, as indicated by a long series examined from Angola (in BMNH). As 
for the anomalous type-locality ascribed to coecum, it seems most likely that the single worker had been 
inadvertently left behind in the vial which originally contained the lujae type-series. This vial was later used 
to hold some Swiss ants and, when they were decanted, the remaining Bondroitia worker had come out 
with them, giving the spurious impression that it had originated in Switzerland along with the genuine Swiss 
ants currently occupying the vial (see Forel, 1909; 1911a; 19116). 

All castes of lujae are known but the worker of saharensis remains to be discovered. Differences 
separating the males and females of the two are given below. 

Material examined 
Zaire: Kasai, Sankura (E. Luja). Angola: Mt Moko (M. C. Day). 

Bondroitia saharensis (Santschi) comb. n. 

Diplomorium saharensis Santschi, 1923: 278. Syntype females, male, Niger: Bilma, ix-xi.1913 (Noel) 
(MNHN) [examined]. 

This species, known only from two females and a single male, is close to lujae. The female is much 
smaller than that of lujae; HW 1 -94 in lujae, HW 1 • 18 in saharensis; maximum width of mesoscutum 2-72 in 
lujae, 1 -56 in saharensis. The female of saharensis is yellow in colour, as opposed to black in lujae, and if the 
size discrepancy between lujae female and worker is expressed in saharensis then workers of the latter will 
be very small indeed. Eyes of the saharensis female are relatively larger than those of lujae, 0-44 x HW in 
the former and 0-24 x HW in the latter. 

Males show the differences in antennal segment count and eye position mentioned in the diagnosis of the 
genus, rendering them easy to differentiate. 

Material examined 
Niger: Bilma (Noel). 



278 B. BOLTON 

DIPLOMORIUM Mayr 

(Figs 3, 6, 12-15) 
Diplomorium Mayr, 1901: 16. Type-species: Diplomorium longipenne Mayr, 1901: 18; by monotypy. 

Worker. Monomorphic myrmicine ants with some size variation but lacking allometric variation. Palp 
formula 2,2. Mandibles usually with 4 teeth but 5 may be present in largest workers; mandibles overlap at 
full closure but do not cross over. Trulleum small and closed. Eyes present and conspicuous, in front of the 
midlength of the sides in full-face view. Median portion of clypeus not suddenly raised, instead swollen and 
evenly broadly transversely convex, lacking longitudinal carinae (Fig. 3). Posteriorly the median portion of 
the clypeus broad and broadly inserted between the widely separated frontal lobes, the clypeus between 
the lobes broader than either of them. Antennae 1 1-segmented, with a weakly 3-segmented club. The basal 
club segment (eighth funicular) much smaller than the other two but still distinctly larger than the seventh 
funicular segment. Promesonotum convex, not flat. Metanotal groove impressed. Metapleural glands 
large and distinct. Propodeal spiracle small and round, situated low on the side, at about the midlength of 
the sclerite or just behind the midlength. Petiole nodiform, subpetiolar process present as a narrow 
cuticular strip. Postpetiole enlarged, in profile more voluminous than the petiole (Fig. 6), in dorsal view 
very broadly attached to the gaster. Sting strong and obviously functional. 

Female. Enormously larger than the conspecific worker, head relatively small in comparison to body size 
(HW 1-54, maximum width of mesoscutum 2-02). Palp formula 2,2. Mandible with 4 teeth, sometimes an 
additional denticle between teeth 2 and 3. Anterior clypeal margin unarmed, triangular and projecting as a 
point medially, overhanging the mandibles (Fig. 14). Median portion of clypeus evenly curved and 
transversely convex, not suddenly raised medially and lacking longitudinal carinae. Clypeus posteriorly 
broadly inserted between the frontal lobes, the outer margins of the latter evenly shallowly convex, not 
pinched in posteriorly. Eyes large and close to midlength of sides. Antennae 11-segmented, with an apical 
club of 3 segments. Mesothoracic axillae large, subtriangular, widely separated on dorsum. Mesoscutum 
and scutellum separated by a broad impression between the axillae (Fig. 15). Metapleural glands 
conspicuous, the orifice with a short row of guard hairs. Propodeal spiracle D-shaped. Venation of 
forewing as Fig. 12, cross-vein m-cu present. Petiole and postpetiole shaped as Fig. 13, the petiolar 
peduncle with a conspicuous anteroventral process. Postpetiolar sernite large and distinctive in profile. In 
dorsal view postpetiole much broader behind than in front and broadly attached to the gaster. 

Male. Unknown. 

In his review of the genera related to Monomorium, Ettershank (1966) decided that Diplomorium and 
Bondroitia were congeneric, based on a comparison of the workers and females of longipenne and lujae. 
The present analysis reverses that decision and treats the two as separate small genera, based upon the 
diagnoses presented above and under Bondroitia, and on the detailed table of differences in worker and 
female also listed under Bondroitia. 

In the past a number of Monomorium species which have 11-segmented antennae have been mis- 
identified as Diplomorium. The following table gives characters which separate the two genera. 



Diplomorium 

Workers 

Median portion of clypeus swollen and evenly 

transversely convex. 
Median portion of clypeus lacking longitudinal 

carinae (Fig. 3) 

Postpetiole in profile enlarged, more voluminous 

than petiole (Fig. 6). 
Postpetiole very broadly attached to gaster. 

Females. As above and also with the following. 
Anterior clypeal margin triangular, coming to a 

point medially (Fig. 14). 
Propodeal spiracle D-shaped (Fig. 13). 



Monomorium 

Workers 

Median portion of clypeus suddenly raised, not 

evenly transversely convex. 
Median portion of clypeus longitudinally 

bicarinate, usually distinctly so but sometimes 

the carinae reduced. 
Postpetiole in profile moderate, usually smaller 

than petiole, sometimes about same size. 
Postpetiole narrowly attached to gaster. 



Anterior clypeal margin not triangular, not coming 

to a point medially. 
Propodeal spiracle usually round, rarely 

otherwise. 



SOLENOPSIS GENUS-GROUP 279 

Of the names include by Ettershank (1966: 100) under Diplomorium only the type-species is retained in 
the genus. The remaining names are dispersed as follows. 
D. coecum: to Bondroitia as a junior synonym of lujae. 
D. cotterelli: to Monomorium as a junior synonym of rosae, a common West African species with 

11-segmented antennae. 
D. lujae: to Bondroitia. 
D. saharensis: to Bondroitia. 
Thus the sole remaining species in the genus is as follows. 

Diplomorium longipenne Mayr 

(Figs 3, 6, 12-15) 

Diplomorium longipenne Mayr, 1901: 18. Syntype workers, females, South Africa: Cape Prov., Port 
Elizabeth (H. Brauns) (NMV; BMNH) [examined]. 

Nothing is known of the biology of this species except that it nests under stones in the ground and has 
been found with Messor capensis (Mayr). It is not known if this represents some sort of relationship 
between the two species or if they were merely nesting in the same site. 

EPELYSIDRIS gen. n. 

(Figs 16, 17) 
Type-species: Epelysidris brocha sp. n. 

Worker. Monomorphic myrmicine ants. Palp formula 3.2. Mandibles elongate-triangular, the masticatory 
margin with 5 sharp teeth which scarcely decrease in size from preapical to basal; preapical to basal teeth 
separated by diastemata. Basal border of mandible equipped with two broad-based bluntly triangular 
lobes, the first close to the basalmost sharp tooth and the second near the trulleum. Trulleum large, 
deformed-triangular in shape and narrowly open below base of second lobe on mandibular basal margin. 
Anterior clypeal margin with a pair of stout triangular teeth. Median clypeal seta present. Anterior 
tentorial pits about half way between antennal sockets and lateral margins of head. Median portion of 
clypeus narrow and conspicuously raised, the convex raised section feebly bicarinate posteriorly and the 
carinae tending to fade out anteriorly. Antennal insertions close together, the width of the posterior 
portion of the clypeus where it passes between the frontal lobes approximately equal to the width of one of 
the frontal lobes. Antennae 12-segmented with a strongly differentiated club of 3 segments. Frontal 
carinae and antennal scrobes absent. Eyes present, small, situated at the midlength of the sides. 
Promesonotum strongly convex, without dorsal sutures. Metanotal groove present and impressed. 
Propodeal spiracle large and circular, close to the midlength of the sclerite. Metapleural glands of 
moderate size, not hypertrophied. Propodeum unarmed but a narrow longitudinal cuticular rim or crest 
present where dorsum meets declivity, the crest continued down each side of the declivity to the small 
rounded metapleural lobes. Declivity without a transverse carina linking the dorsalmost points of the 
metapleural lobes. Petiole with a long anterior peduncle which is subtended by a narrow elongate ventral 
processes. Petiolar spiracle at the node. Nodes of both petiole and postpetiole strongly developed, shaped 
as in Fig. 16. Sting long and strong, somewhat flattened and subspatulate apically. 

Female and male. Unknown. 

Epelysidris is easily diagnosed among members of the Solenopsis-grpup by the remarkable pair of lobes 
on the basal border of each mandible, unknown in any other genus of the group. The structure of the 
mandibles and clypeus together, combined with the 3,2 palp formula, isolates Epelysidris from all other 
myrmicine ant genera. 

Epelysidris appears at first glance to have affinities with the Neotropical genus Megalomyrmex as it 
parallels to some extent the habitus of certain species in the M. modestus-group. This impression tends to 
be reinforced by the fact that the anterior tentorial pits are about half way between the antennal sockets 
and the lateral margins of the head in Epelysidris, a condition thought by Ettershank (1966) to be 
diagnostic of Megalomyrmex and its allies and not to occur in Monomorium and its immediate relatives. It 
is now strongly suspected that the position of the anterior tentorial pit may depend to a large extent on the 
degree of approximation of the antennal sockets in Monomorium and its relatives. Thus in forms where the 



280 B. BOLTON 

posteromedian portion of the clypeus is strongly raised and narrow the antennal sockets are very close 
together and have apparently migrated towards the midline away from the anterior tentorial pits, leaving 
the latter in a Megalomyrmex-\ike position rather than close to the sockets as in most Monomorium . 
Analysis of apomorphic characters of Epelysidris and the Megalomyrmex modestus-group shows that the 
two have most probably acquired their habitus similarities convergently. 

Characters regarded as apomorphic in the M. modestus-group include the specialization of the 
mandibular masticatory margin by the development of multiple denticles, and the presence of a transverse 
rim or carina across the apices of the metapleural lobes. Epelysidris is plesiomorphic in both these cases, 
with 5 ordinary teeth on the masticatory margin of the madible and lacking the transverse rim between the 
metapleural lobes. 

Conversely characters regarded as apomorphic in Epelysidris include the development of lobes on the 
mandibular basal margin, the presence of large triangular teeth on the anterior clypeal margin, and the 
development of narrow cuticular crests down each side of the propodeal declivity. The M. modestus-group 
is plesiomorphic in these, with unarmed basal mandibular margins, lacking clypeal teeth, and lacking 
cuticular crests on the propodeal declivity. 

The real affinities of Epelysidris appear to lie with Monomorium and its immediate allies, from which it 
has evolved by gross modification and specialization of the mandibles and clypeus. Differences in the 
mandible between Epelysidris and those Monomorium species with 5 teeth include lengthening and 
narrowing of the blade in the former and the opening of diastemata between the teeth following the 
preapical, and the autapomorphic development of lobes on the basal border. In the case of the clypeus 
Epelysidris has modified the median portion by narrowing and raising it up very markedly, and narrowing 
its posterior section between the antennal insertions. The pair of longitudinal clypeal carinae, character- 
istic of Monomorium, is very reduced and fades out anteriorly in Epelysidris. On the other hand the 
pair of teeth on the anterior clypeal margin, which mark the apices of the clypeal carinae in many 
Monomorium species, are very much enlarged in Epelysidris and are divorced from the carinae altogether. 

The single species currently recognized in the genus is as follows. 

Epelysidris b roc ha sp. n. 

(Figs 16, 17) 

Holotype worker. TL 3-8, HL 0-78, HW 0-64, CI 82, SL 083, SI 130, PW 0-46, AL 1-02. 

Apical and preapical of the 5 mandibular teeth not separated by a diastema, but with a diastema between 
each of the remaining teeth. All teeth narrowly triangular and sharp. First lobe on basal margin of 
mandible more broadly triangular than the basal tooth and conspicuously more bluntly rounded, close to 
the basalmost tooth of the masticatory margin but directed posteriorly when the mandibles closed. Second 
lobe confluent with first basally, slightly lower and more broadly triangular than the first lobe. Blades of 
mandibles unsculptured except for small hair-pits. Mandibles downcurved, rather more strongly so at apex 
so that in full-face view the apical tooth appears to be directly below the preapical. PF 3,2. Anterior clypeal 
margin with a slightly prominent median section which is bounded by a pair of sharp triangular teeth; the 
margin between the teeth more or less transverse. Median clypeal seta conspicuous. Median portion of 
clypeus narrow and suddenly raised, evenly convex anteriorly but posteriorly with vestiges of a pair of 
clypeal carinae which converge posteriorly. Space between these carinal vestiges flat to very shallowly 
transversely concave. Posteromedian section of clypeus very narrow where it passes between the small 
frontal lobes; the latter not wholly concealing the condylar bulbs of the scapes. Antennal scapes long 
(SI > 125), when laid straight back from their insertions considerably exceeding the occipital margin. 
Funicular segments 1-8 ca 0-48, the club (funicular segments 9-11) ca 0-70; club segments relatively 
narrow but very much longer than any of the preceding funicular segments. Eyes situated at about the 
midlength of the sides of the head. Eyes small, about 0- 13 x HW, consisting of an outer ring of 8 ommatidia 
surrounding a single central ommatidium. Outline shape of head as in Fig. 17. Shape of alitrunk, petiole 
and postpetiole as shown in Fig. 16. Metanotal groove broad and conspicuously impressed, traversed by 
short but distinct cross-ribs. Propodeal spiracle large, with a circular orifice which is directed somewhat 
posteriorly, not opening flush with the side of the sclerite. Propodeal dorsum and declivity meeting in a 
blunt angle in profile, the declivity almost vertical and bounded on each side by a very narrow cuticular 
crest which is continuous with the metapleural lobes below and just reaches onto the dorsum above. 
Metapleural lobes small and rounded. Anterior peduncle of petiole long and narrow, subtended by a fine 
strip-like anteroventral process. Petiolar spiracle at the node. Postpetiole about the same size as the petiole 
node in profile but somewhat more broadly rounded. In dorsal view the petiole node broader than long; 
postpetiole also broader than long but more nearly subglobular than the petiole and somewhat narrower. 
All dorsal surfaces of the head and body with elongate simple standing hairs. Antennal scapes and middle 



SOLENOPSIS GENUS-GROUP 281 

and hind legs with suberect to subdecumbent projecting hairs, the longest of which are equal to or slightly 
longer than the width of the appendage on which they arise. Head smooth and shining, unsculptured except 
for scattered hair-pits. Promesonotum as head but the propodeal dorsum with faint shagreening. 
Mesopleuron finely and densely punctulate-shagreenate and the metapleuron with a few longitudinal 
rugulae; otherwise sides of alitrunk unsculptured and shining. Petiole and postpetiole nodes and gaster 
unsculptured except for hair-pits. Peduncle of petiole with fine punctulation dorsolaterally. Colour 
uniform dull yellow. 

Paratype workers. TL 3-7-4-0, HL 0-76-0-80, HW 0-62-0-64, CI 80-83, SL 0-78-0-83, SI 126-132, PW 
0-44-0-48, AL 0-96-1-02 (7 measured). As holotype but maximum diameter of eye 0-11-0-13 x HW and 
the eye with 9-12 ommatidia in total. The eye consists of an outer ring of 8-9 ommatidia which encloses 1-3 
central ommatidia. 

Holotype worker, East Malaysia: Sarawak, Mt Dulit, 4000 ft, moss forest, 21.x. 1932, Oxford Univ. 
Expd. B. M. 1933-254. Ants nest in soil under moss and rocks {B. M. Hobby & A. W. Moore) (BMNH). 
Paratypes. 8 workers with same data as holotype (BMNH; MCZ). 



PHACOTA Roger gen. rev. 

Phacota Roger, 1862a: 260. Type-species: Phacota sichelii Roger, 1862a: 262; by monotypy. 
Phacota Roger; Ettershank, 1966: 82 [as synonym of Monomorium]. 

Worker. Head in full-face view almost circular, in profile lenticular. Eyes situated behind the midlength of 
the sides. Mandibles short and with parallel borders, the apical margin with 4 teeth. Clypeus large and 
strongly vaulted, its anterior border feebly emarginate medially. Antennae with 11 segments, the club of 2 
segments. Scape long and easily surpassing the occipital margin of the head. Mesonotum strongly 
saddle-shaped. Propodeum unarmed. Petiole short-cylindrical anteriorly, thickened behind, apparently 
without a strongly differentiated node. Postpetiole nodiform. Gaster much larger than head. 

Female and male. Unknown. 

Based on a single specimen from Malaga, Spain, sichelii has been an enigma from the day of its 
description to the present. The holotype appears to have been lost or destroyed at some time in the past and 
the species has never been found again. 

From the original description, and assuming that the antennal segment count is correct, it seems likely 
that Phacota is correctly placed in the Solenopsis-group close to Monomorium; at least no other more 
obvious placement springs to mind. I strongly suspect that the single specimen may not truly have been a 
worker, as it has been interpreted in all previous attempts to understand this taxon, but may well have been 
an apterous ergatoid female. Characters mentioned in the original description which fuel this suspicion 
include the fact that the head is small, much smaller than the large gaster, and the mesonotum is 
saddle-shaped, a feature frequently observed in apterous females of the Monomorium salomonis-group. 
Nevertheless, with the sichelii holotype lost this must remain supposition and the description must continue 
to be treated as that of a worker, until more evidence comes to light. 

Earlier attempts to understand and place the genus Phacota (e.g. Forel, 1917; Wheeler, 1922; and 
perhaps even Ettershank, 1966) were undoubtedly much influenced by Emery's (1895a) addition of a 
second species to Phacota. This species, Phacota noualhieri Emery, was based on a single worker retrieved 
from a nest of Monomorium salomonis (L.) in Algeria. Like sichelii, noualhieri has never been found 
again, and Emery's conjecture that it is a social parasite (or rather the degenerate worker of a socially 
parasitic female) may well be correct. Emery (1895a) pointed out that his noualhieri was radically different 
from sichelii in many respects but resembled it in having 11 antennal segments and a 2-segmented club. 
These were the characters which decided him to add noualhieri to Phacota. However, an examination of 
the holotype of noualhieri during the course of the present survey showed it to be most definitely a member 
of the Monomorium salomonis-group and to have 12-segmented antennae with a 3-segmented apical club. 
Emery's miscount of the number of antennomeres seems to have been caused by the specialized apical and 
preapical funicular segments of noualhieri, as described below. 

Accepting that Roger's interpretation of the antennae of sichelii was correct, it seems best to remove 
Phacota from the synonymy of Monomorium and to treat it once more as a valid monotypic genus, at least 
for the time being. Any doubts about whether the correct placement for Phacota is close to Monomorium 



282 B. BOLTON 

or actually within the synonymy of that genus must be set aside until actual specimens of sichelii can again 
be found. The single species currently include in Phacota is as follows. 

Phacota sichelii Roger 

Phacota sichelii Roger, 1862a: 262, pi. 1, fig. 20. Holotype worker (?), Spain: Malaga (Sichel) (not in 
MNHU, presumed lost or destroyed). 

The only other species described in Phacota, noualhieri, is now transferred to the Monomorium 
salomonis-group . A redescription of the holotype and only known specimen of noualhieri follows. 

Monomorium noualhieri (Emery) 

Phacota noualhieri Emery, 1895a: 299, figs 1 a-d. Holotype worker, Algeria: Biskra (Noualhier) (MCSN) 

[examined]. 
Monomorium noualhieri (Emery) Ettershank, 1966: 91. 

Holotype worker (redescription). TL 3-3, HL 0-84, HW 0-62, CI 74, SL 0-70, SI 113, PW 0-42, AL 0-98. 
Mandibles with narrow blades, the masticatory margin with 4 sharp teeth. Apical tooth acute, narrow 
and disproportionately long, well over twice the length of the second tooth. Mandibles unsculptured and 
smooth. Palp formula 1,2, the single maxillary palp segment short clavate, almost bulbous. Antennal 
segmentation almost obliterated by partial fusion of the funicular segments, the limits of individual 
segments difficult to discern. Antennae with 12 segments, the apical club of 3 segments (not 11 and 2 as in 
the original description). The two apical club segments are flattened from side to side, the apical more so 
than the preapical, and almost fused together so that their junction is difficult to see. The apical club 
segment is slightly concave on its inner surface and convex on its outer. This may be artifact of preservation 
but both antennae are alike. Anterior clypeal margin with the median portion broadly evenly convex. 
Median portion of clypeus broadly convex across, without carinae. Frontal lobes very small and the 
posterior margin of the clypeus between them with the suture obliterated. Eyes fractionally behind the 
midlength of the sides, their maximum diameter about 0-22 x HW. Promesonotum evenly long-convex, 
the metanotal groove shallowly impressed. Propodeum on a lower level than the promesonotum and 
evenly shallowly convex, with the dorsum rounding broadly into the declivity. Petiole node in profile 
subglobular, with an extremely short thick peduncle; subsessile in appearance. In dorsal view the petiole 
node slightly broader than long, not sharply differentiated from its anterior peduncle and the latter scarcely 
narrower than the node. Postpetiole by contrast very reduced, occupying less than half the volume of the 
petiole and longer than broad. Dorsal surfaces of entire head and body lacking standing hairs. Entire ant 
glossy brown, smooth and shining, unsculptured except for faint superficial vestiges in places. 

Santschi (1919a) suggested that noualhieri may belong to his male-based genus Paraphacota, and later 
(Santschi, 1927) even went so far as to designate noualhieri as a second type-species for Paraphacota after 
he had discovered that his original type-species was a male of Monomorium subopacum (Smith). This 
fruitless shifting of noualhieri from genus to genus, without ever the holotype being examined, only served 
to cloud the issue and did nothing to fix its real identity, which is now unequivocally established as a 
member of the Monomorium salomonis-group. 

M. noualhieri was collected in a nest of M. salomonis in Algeria. The inquiline species M. santschii 
(Forel) also uses salomonis as a host species. Is there a possibility that noualhieri represents a throwback, 
an accidentally produced worker of santschii in a species otherwise known to have lost its worker caste? At 
present I consider the possibility to be extremely remote and suspect that santschii is permanently a 
worker less inquiline and that noualhieri is truly an isolated species, representing the somewhat degenerate 
worker caste of an otherwise unknown socially parasitic female. 

ALLOMER US Mayr 

Allomerus Mayr, 1877: 873. Type-species: Allomerus decemarticulatus Mayr, 1877: 874; by subsequent 
designation of Wheeler, 1911: 158. 

For current diagnosis see Ettershank, 1966: 111. 

The definition of this small genus given by Ettershank (1966) requires a little modification because of a 
rather aberrant species described by Kempf (1975), which has been the only addition to the genus since 



SOLENOPSIS GENUS-GROUP 283 

1966. This species, A. vogeli Kempf , shows that the antennal segment count in the genus as a whole may be 
7-11 and that the propodeum may be unarmed or dentate . A further modification to the definition involves 
the dental count. Ettershank (1966) gives 4 as the number of teeth in Allomerus workers, but in the 
material which I have examined and in Kempf 's (1975) species, the predominant count is 5 teeth. 

At genus-level Allomerus now seems fairly well defined and compact, its females and workers isolated 
within the group by their shield-like evenly rounded clypeal structure , lack of clypeal carinae and reduction 
of fringing setae on the anterior clypeal margin, sometimes until only the median seta is present. These 
clypeal structures plus the conspicuous apomorphic character of basally constricted antennal club 
segments, PF 3,2, and relatively widely separated antennal insertions, all serve to identify the genus. 

The general habitus of Allomerus is very similar to that of the South African monotypic genus 
Diplomorium. The overall similarity may be the result of convergence as Diplomorium lacks basally 
constricted antennal club segments (but does have a modified club) , has PF 2 ,2 , and retains cross-vein m-cu 
in the forewing. Set against these differences, however, is the structural similarity of the clypeus and 
associated structures in both genera. The position of the anterior tentorial pit, which Ettershank (1966) 
used to diagnose and differentiate his Monomorium- and Megalomy rmex-groups, and which thus 
separated Diplomorium from Allomerus, is not such a clear-cut character as first seemed to be the case. In 
Allomerus it was maintained that the anterior tentorial pit was about half way between the antennal socket 
and the lateral clypeal margin, this being part of the diagnosis of the relatives of Megalomyrmex. In 
material which I have examined the pit in Allomerus is certainly closer to the antennal socket than to the 
lateral clypeal margin, though not as close as in Diplomorium. As Kempf (1974) pointed out, the position 
of the pit varies even between Solenopsis and Oxyepoecus, the two members of Ettershank's Solenopsis- 
group, so too much emphasis should not be placed on this character alone. 

There is therefore a possibility that Allomerus and Diplomorium are close in a phylogenetic sense, but 
further investigation is essential to prove or disprove the contention. Perhaps the discovery of the still 
unknown male of Diplomorium would shed a little more light on the matter. 

In Allomerus the species-level taxonomy of this small neotropical genus remains in a very confused state, 
with many infraspecific names of dubious status still extant (Kempf, 1972). 

ANTICHTHONIDRIS Snelling 

Antichthonidris Snelling, 1975: 5. Type-species: Monomorium denticulatum Mayr, 1887: 614; by original 
designation. 

For diagnosis of the genus see Snelling (1975); for distribution and notes on species see Snelling & Hunt 
(1975). 

This small Chilean and southern Argentinian genus contains only two species and has its origins in 
Ettershank's (1966) genus Nothidris (see there). The latter was created to hold three Neotropical species 
which Ettershank decided to separate from Chelaner (itself now a junior synonym of Monomorium). 
Whilst reviewing the Chilean fauna Snelling (1975) noted that two of the species included in Nothidris, 
denticulata (Mayr) and bidentata (Mayr), were generically distinct from the third (type-species) of the 
genus Nothidris, latastei (Emery). Accordingly he created the genus Antichthonidris to accommodate the 
first two species. 

As both species of Antichthonidris are frequently found sharing a single nest it has been postulated that 
one is socially parasitic upon the other, or perhaps even dulotic (see notes and references in Ettershank 
(1966) and in Snelling & Hunt (1975)) but no direct investigation of the real relationship between the two 
has ever been undertaken. 

Snelling separated his new genus in the females and workers on characters of palp formula (Nothidris PF 
4,3; Antichthonidris PF 2,2), presence of simple tibial spurs on the middle and hind legs in Nothidris, and 
the presence of a larger and more prominent median clypeal lobe in Antichthonidris. The male of the latter 
had PF 3,2 and well-developed notauli on the mesoscutum. 

The size and prominence of the median clypeal lobe can be discounted in terms of diagnosing the genus 
as it varies considerably in most genera of the group. Snelling apparently used it just to differentiate his 
genus from Nothidris alone. An interesting point which he raised is that the taxonomic position of 
Antichthonidris may lie outside the Solenopsis-group of genera. He said, 'it is evident that these ants do not 
belong among the Monomorium-Solenopsis series of genera, since the males of these groups lack notauli.' 
Snelling continued by saying that some worker and female characters suggested a relationship with 
Stenamma, but that the male habitus was quite different, and concluded that it 'seems best to leave 
Antichthonidris unassigned until all myrmicine genera can be re-evaluated.' 

Having examined both Antichthonidris species I must conclude that membership in the Solenopsis-group 



284 B. BOLTON 

as defined here is the best fit that can currently be achieved for the genus. Snelling's objection that males of 
the Solenopsis-group lack notauli is discounted as the character is very variably developed in Monomorium 
and ranges from strong to absent in the Australasian fauna alone. In workers and females the position of 
the petiolar spiracle in Antichthonidris is characteristic of the Solenopsis-group and not of Stenamma where 
the spiracle tends to be very close to the anterior articulation of the peduncle. 

The Australian fauna (material examined from ANIC) has revealed a few indeterminate species which 
appear very similar to the type-species of Antichthonidris and are almost certainly congeneric with it. In 
general all main characters are the same but the Australian forms mostly have longer propodeal spines and 
more stocky postpetiole nodes. Such characters are not presently considered useful at genus-level. Only a 
detailed study of the Australasian fauna will show if these species grade into Monomorium, if they are 
really congeneric with the Neotropical Antichthonidris, and if this latter genus represents merely a 
Neotropical isolate of the much more extensive Australasian fauna, as appears to be the case with 
Nothidris. 

NOTHIDRIS Ettershank 

Nothidris Ettershank, 1966:105. Type-species: Monomorium latastei Emery, 1895c: 10; by original 
designation. 

In his original description of Nothidris Ettershank included three species, latastei, bidentata, and 
denticulata. Snelling (1975) removed the last two names to a separate genus, Antichthonidris (see above), 
described a new species in Nothidris, cekalovici, and transferred another species, bicolor (Ettershank), out 
of Megalomyrmex into Nothidris. The genus as presently constituted thus contains three closely related 
species which appear to be restricted in their distribution to relatively high altitudes in Chile. Snelling 
(1975) and Snelling & Hunt (1975) give keys to the species of Nothidris. 

Prior to Ettershank's (1966) creation of Nothidris its type-species, latastei, had been included, along with 
numerous Australian forms, in a subgenus of Monomorium called Notomyrmex (see Emery, 1922). In 
Ettershank's study Notomyrmex was given as a junior synonym of Chelaner, which he treated as a valid 
genus, excluding from the latter only those southern Neotropical forms isolated to constitute his genus 
Nothidris. Ettershank maintained that Nothidris was related to Megalomyrmex, which is true only insofar 
as all genera in this group are related, but he reiterated that the general habitus of Nothidris was that of the 
Australasian species referred by him to Chelaner (the latter being regarded in this paper as a junior 
synonym of Monomorium). With the removals from and additions to Nothidris carried out by Snelling 
(1975) it became apparent that Emery (1922) was correct in associating latastei with the Australasian fauna, 
and further that Nothidris represents nothing more than a specialized southern Neotropical fraction of that 
fauna. Ultimately it may become necessary to synonymize Nothidris under Monomorium. 

The reasoning behind this possibility lies in the breakdown and obliteration of diagnostic characters 
supposedly separating Nothidris from those Australasian species-groups formerly constituting Chelaner in 
the sense of Ettershank (1966). All species currently retained in Nothidris, i.e. , excluding the two removed 
by Snelling (1975), should fit Ettershank's diagnosis after the palp formula character has been modified to 
take Snelling's exclusions into account. Ettershank gives: 

(1) The palp formula in Nothidris is 4,3; in Chelaner it is 2,3 or 2,2. 

(2) The anterior tentorial pits in Nothidris are about half way between the antennal sockets and the 
lateral margins of the clypeus; in Chelaner the anterior tentorial pits are situated very near the antennal 
sockets. 

The palp formula holds, for what it is worth. All current Nothidris have PF 4,3 in the worker and this 
count remains unknown in Monomorium as presently defined. Unfortunately Monomorium species are 
now known which show palp formulae of 5,3; 3,3; 2,3; 2,2; 1,2; and 1,1. Notice that the only count missing 
from this otherwise evenly stepped morphoclinal reduction is 4,3, the palp formula of Nothidris. 

As for the anterior tentorial pits, they are no further away from the antennal sockets in N. latastei than 
they are in many Australasian Monomorium (= Chelaner) species; the character has no validity in this case 
and does not exist in reality. The detailed structure of all aspects of the head in Nothidris species is the same 
as that shown in Australian Monomorium such as sanguinolentum Wheeler, turned (Forel) and rubriceps 
Mayr, and the modification of the propodeum into small bilaterally flattened teeth or prominent angles, at 
the junction of the dorsum and declivity, shows the same kinds of development in both groups. 

One character which Ettershank (1966) mentions as diagnostic of Chelaner is the presence of a 
vestibulate propodeal spiracle, which is not mentioned for any other genus in his review. Throughout the 
Australian Monomorium species-groups which formerly constituted Chelaner there is considerable 
variation in the expression of this character, but it is also present in Nothidris, being conspicuous in latastei 
(the type-species) and bicolor, less obvious in cekalovici. 



SOLENOPSIS GENUS-GROUP 285 

Thus Nothidris is at best an extremely feeble genus, maintained as distinct more by its zoogeography 
than its morphology, which is an unsatisfactory state of affairs. I strongly suspect that a taxonomic study of 
the Australian Monomorium species-groups, especially the core-groups of larger species which formerly 
constituted Chelaner, will see the formal synonymy of Nothidris under Monomorium. 

MEGALOMYRMEX Forel 

Megalomyrmex Forel, 1884: 371. Type-species: Megalomyrmex leoninus Forel, 1884: 372; by monotypy. 

For diagnosis and current synonymy see Ettershank, 1966: 101. 

Ettershank (1966) listed 25 names in this genus, of which only three represented infraspecific taxa. Since 
then Kempf & Brown (1968) have established a fairly extensive synonymy for one species; Kempf (1970) 
has added 3 more species to the genus, and Snelling (1975) has correctly removed bicolor from the genus 
and transferred it to Nothidris (see there). Thus Megalomyrmex currently contains 22 named forms but 
taxa remaining to be described will probably bring this total up to 25-30. 

The form of the mandible found in the small M. modestus-group contradicts character (1) of the 
genus-group diagnosis. The form of dentition in this species-group is, however, very obviously a secondary 
proliferation from a sparsely dentate original pattern, and is not homologous with the serially multidentate 
mandibles seen in some other myrmicine genus-goups, where the teeth are all well defined and regularly 
decrease in size from apex to base. In the M. modestus-group either the original 5 teeth become 
interspersed with small denticles or a series of minute denticles develops behind the preapical or behind the 
third tooth. 

Megalomyrmex is closely related to Monomorium but is separated by the presence in the former of an 
arched transverse rim or carina which traverses the propodeal declivity between the uppermost parts of the 
metapleural lobes, and the possession of PF 4,3 or 3,2, combinations not presently known from 
Monomorium. Despite this the genus remains poorly differentiated from Monomorium, especially the 
extensive Australasian fauna of the genus. Ettershank (1966) records a count of 4 malpighian tubules from 
Monomorium and 5 from Megalomyrmex. Unfortunately only very few species have been examined for 
this character so its universality and usefulness cannot presently be ascertained. 

SOLENOPSIS Westwood 

Solenopsis Westwood, 1841: 86. Type-species: Solenopsis mandibularis Westwood, 1841: 86 (= Atta 
geminata, F., 1804: 423); by monotypy. 

For diagnosis and current synonymy see Ettershank, 1966: 134. 

Of the 10 genus-level synonyms of Solenopsis proposed by Ettershank (1966) only Diplorhoptrum Mayr 
has so far been challenged. Baroni Urbani (1968a) suggested that this name should be retrieved from the 
synonymy and applied as a valid genus to hold the species related to fugax (Latreille). The suggestion has 
been accepted by several authors in the Palaearctic region (e.g. Kutter, 1977; Bernard, 1977; Collingwood, 
1978, 1979; Onoyama, 1980) whilst dealing with local faunas, and elsewhere the name has been used as a 
subgenus (e.g. Thompson, 1982), but it has not gained universal acceptance and elsewhere Diplorhoptrum 
continues to be treated as a synonym of Solenopsis (e.g. Brown, 1973; Kempf, 1972; Snelling, 1975; 
Krombein etal., 1979; and this current review). 

Baroni Urbani's (1968a) arguments were based on characteristics of the male genitalia and his results 
were obtained by comparison of members of the fugax-group with members of the geminata-group . Whilst 
accepting that the differences pointed out by Baroni Urbani are real, I am unable to regard them as being 
significant above the species-group level. The taxonomic level of the genitalic characters is certainly far 
lower than those utilized to discriminate genera, not only in the Solenopsis-group but throughout the 
Myrmicinae, and in general are at the level used to distinguish species-groups. No one I think would argue 
that fugax and geminata are not different at species-group level, but the higher characters which link them 
are so strong and consistent that there is no reason to regard the two groups as belonging to different 
genera. Finally, the male genitalic characters of other Solenopsis species-groups have not been compared, 
so there is no real evidence that the characters noted by Baroni Urbani (1968a) function on a world-wide 
basis even at species-group level. 

Kutter (1977) gives an antennal character to separate the female castes of Diplorhoptrum and Solenopsis 
(properly the fugax- and geminata-group?,). This is a very minor character indeed, devised solely to 
separate the European species, and is meaningless on a world-wide basis, the only basis upon which 



286 B. BOLTON 

genus-level characterizations can be successfully organized. Again, the taxonomic level of Kutter's 
character is far below that considered useful in separating genera. Collingwood (1979) merely gives the 
main diagnostic characters of Solenopsis and adds Baroni Urbani's (1968a) male genitalic feature to 
differentiate Diplorhoptrum. 

Apart from the large conspicuous species which constitute the geminata-group the species-level 
taxonomy of Solenopsis is quite frankly in an appalling condition. On the one hand the Neotropical region 
contains dozens of minute species, some of them extremely abundant, which remain totally univestigated. 
On the other hand the western Palaearctic has suffered enormously from gross oversplitting within the 
fugax-group, the only native species-group in the region. Bernard (1949, 1977) has himself described an 
utterly unbelievable 15 species from southern France alone, on top of the older established named forms. 
He maintains (Bernard, 1977) that 20 species occur in France, though his keys give only 18 names. There is 
no doubt that at species-level Solenopsis is greatly in need of synthesizing taxonomic studies conducted on a 
world-wide basis. Parochialism and 'mihi-itch' have created an overabundance of vague and unrecogniz- 
able taxa in this important genus; serious investigation of its species-level taxonomy is long overdue. 

OXYEPOECUS Santschi 

Oxyepoecus Santschi, 1926c: 6. Type-species: Oxyepoecus bruchi Santschi, 1926c: 6, figs A-D; by 
monotypy. 

For definition of the genus and its current synonymy see Ettershank (1966) and Kempf (1974); the latter 
also provides a species-level revision, the first description of a male, and keys. Genus-level synonyms given 
in these publications remain unchallenged. 

With 11 species currently recognized Oxyepoecus constitutes a well-defined and somewhat isolated small 
Neotropical genus of the Solenopsis-group. Most samples of this genus have been found as foragers 
retrieved from leaf litter samples, but two Oxyepoecus species are inquilines in nests of Pheidole species 
and a third may be an inquiline in nests of Solenopsis, though evidence supporting the latter is 
circumstantial and insecure. Kempf (1974) summarizes what little is known of these species but is unable to 
say whether the two certain inquilines are temporary or permanent social parasites, or whether a 
xenobiotic lifeway is involved. 

Both Ettershank (1966) and Kempf (1974) agree that Oxyepoecus is closely related to the much larger 
genus Solenopsis. The former author placed the two genera together in a single group but the latter was 
unsure that Ettershank's genus-groups were sufficiently closely defined, especially as the then newly 
discovered male of Oxyepoecus resembled that of Megalomyrmex more than that of Solenopsis. 

The present review has little to add at genus-level to the previous studies. The close relationship of this 
genus with Solenopsis is reaffirmed, strong linking characters including those given in the previous studies. 
Consistent characters separating the two genera are as follows. 
Solenopsis Oxyepoecus 

Antennal club of 2 segments in the worker and Antennal club of 3 segments in the worker and 

female. female. 

Antennae with 10 segments in worker. Antennae with 11 segments in worker. 

Propodeum unarmed in worker and female. Propodeum dentate in worker and female. 

First funicular segment globular in male. First funicular segment cylindrical in male. 

Mandibles with 1-2 teeth in male. Mandibles with 4 teeth in male. 

CAREBARELLA Emery 

Carebarella Emery, 1905: 137. Type-species: Carebarella bicolor Emery, 1905: 138; by monotypy. 

For diagnosis and current synonymy see Ettershank, 1966: 113. 

This small and poorly understood genus remains as Ettershank left it, the only addition since that time 
being the description of a fourth species, C. alvarengai, by Kempf (1975), based on an alate female. 

Ettershank placed Carebarella among the relatives of Megalomyrmex but I suspect that the genus may in 
fact be closer to Solenopsis, as Emery (1922) indicated. The reasons for this include the presence of 
geniculate maxillary palps in Carebarella along with a clypeal structure which appears derived, in the 
worker at least, from a Solenopsis-like ancestral form. Also there is dimorphism of antennal form between 
worker and female in Carebarella, a feature also encountered in Solenopsis but not in the allies of 
Megalomyrmex. 



SOLENOPSIS GENUS-GROUP 287 

MONOMORIUM Mayr 
(Figs 18-100) 

Monomorium Mayr, 1855: 452. Type-species: Monomorium monomorium nom. n. (replacement name for 

Monomorium minutum Mayr, 1855: 453, junior secondary homonym of Atta minuta Jerdon, 1851: 105 

[= M. pharaonis (L.), 1758: 580]); by monotypy. [See note 1, below.] 
Trichomyrmex Mayr, 1865: 19. Type-species: Trichomyrmex rogeri Mayr, 1865: 19; by monotypy. 

[Synonymy by Ettershank, 1966: 82.] 
Lampromyrmex Mayr, 1868: 93. Type-species: Monomorium may rianum Wheeler, 1915: 45 (replacement 

name for Lampromyrmex gracillimus Mayr, 1868: 95 (ex Baltic amber), junior secondary homonym of 

Monomorium gracillimum (Smith), 1861a: 34); by monotypy. [Synonymy by Wheeler, 1915: 45; 

Ettershank, 1966: 82.] 
Holcomyrmex Mayr, 1878: 671. Type-species: Holcomyrmex scabriceps Mayr, 1878: 672; by subsequent 

designation of Bingham, 1903: 280. [Synonymy by Ettershank, 1966: 82.] 
Epoecus Emery, 1893a: cclxxvi. Type-species: Epoecus pergandei Emery, 1893a: cclxxvi; by monotypy. 

[Synonymy by Ettershank, 1966: 82.] 
Wheeleria Forel, 1905: 171. Type-species: Wheeleria santschii Forel, 1905: 171; by monotypy. [Junior 

homonym of Wheeleria Tutt, 1905: 37 (Lepidoptera).] 
Wheeleriella Forel, 1907c: 145 (replacement name for Wheeleria Forel, 1905: 171). [Synonymy by 

Ettershank, 1966: 82.] 
Epixenus Emery, 1908a: 556. Type-species: Monomorium advena Brown & Wilson, 1957: 244 (replace- 
ment name for Epixenus andrei Emery, 1908a: 557, junior secondary homonym of Monomorium andrei 

Saunders, 1890: 204); by subsequent designation of Wheeler, 1911: 163. [Synonymy by Brown & 

Wilson, 1957: 244.] 
Mitara Emery, 1913: 261 [as subgenus of Monomorium]. Type-species: Monomorium laeve Mayr, 1876: 

101; by original designation. [Synonymized with Monomorium (Lampromyrmex) by Emery, 1922: 183 

and Wheeler, 1922: 162.] 
Chelaner Emery, 1914: 410 [as subgenus of Monomorium}. Type-species: Monomorium (Chelaner) 

forcipatum Emery, 1914: 410; by subsequent designation of Emery, 1922: 168. [Raised to genus by 

Ettershank, 1966: 93.] Syn. n.. 
Notomyrmex Emery, 1915: 190 [as subgenus of Monomorium]. Type-species: Atta antarctica Smith, 1858: 

167; by original designation. [Synonymized with Chelanerby Ettershank, 1966: 93.] [See note 2, below.] 
Xeromyrmex Emery, 1915: 190 [as subgenus of Monomorium]. Type-species: Formica salomonis L. , 1758: 

580; by original designation. [Synonymy by Ettershank, 1966: 82.] 
Parholcomyrmex Emery, 1915: 190 [as subgenus of Monomorium}. Type-species: Myrmica gracillima 

Smith, 1861a: 34 [= Monomorium destructor (Jerdon), 1851: 105]; by original designation. [Synonymy 

by Ettershank, 1966: 82.] 
Syllophopsis Santschi, 1915: 259 [as subgenus of Monomorium]. Type-species: Monomorium modestum 

Santschi, 19146: 17; by monotypy. [Raised to genus by Santschi, 1921ft: 119.] Syn. n. 
Corynomyrmex Viehmeyer, 1916: 134 [as subgenus of Monomorium]. Type-species: Monomorium 

(Corynomyrmex) hospitum Viehmeyer, 1916: 133; by monotypy. [Provisional synonymy by Ettershank, 

1966: 82, here confirmed.] 
holcomyrmex Santschi, 1917: 296 [as subgenus of Monomorium}. Type-species: Monomorium sant- 

schianum Ettershank, 1966: 92 (replacement name for Holcomyrmex santschii Forel, 1907a 1 : 203, junior 

secondary homonym of Monomorium santschii (Forel), 1905: 171); by original designation. [Synonymy 

by Ettershank, 1966:82.] 
Paraphacota Santschi, 1919a: 90. Type-species: Paraphacota surcoufi Santschi, 1919a: 90 [= Monomorium 

subopacum (Smith), 1858: 127]; by monotypy. [Synonymy by Santschi, 1927: 243.] 
Equestrimessor Santschi, 1919a: 92 [as subgenus of Monomorium]. Type-species: Holcomyrmex chobauti 

Emery, 1897a: 418; by subsequent designation of Donisthorpe, 1943ft: 644. [Synonymy by Ettershank, 

1966: 82.] 
Xenhyboma Santschi, 1919c: 405. Type-species: Xenhyboma mystes Santschi, 1919c: 405 [= Monomorium 

medinae Forel, 1892ft: 454]; by monotypy. [Provisional synonymy by Ettershank, 1966: 82, confirmed by 

Espadaler, 1982: 112.] 
Protholcomyrmex Wheeler, 1922: 162 [as subgenus of Monomorium]. Type-species: Monomorium 

rothsteini Forel, 1902ft: 444; by original designation. [Synonymized with Chelaner by Ettershank, 1966: 

93.] 
Ireneidris Donisthorpe, 1943a: 81. Type-species: Ireneidris myops Donisthorpe, 1943a: 81 [= Mono- 
morium talpa Emery, 1911: 252]; by original designation. [Synonymy by Ettershank, 1966: 82.] 



288 B. BOLTON 

Schizopelta McAreavey, 1949: 14. Type-species: Schizopelta falcata McAreavey, 1949: 15; by original 

designation. [Synonymized with Chelanerby Ettershank, 1966: 93.] 
Pharaophanes Bernard, 1952: 238 (attributed to Santschi; without description and without designation of 

type-species). [Nomen nudum.] 

Note 1, the type-species of Monomorium. 

Since its inception as a genus the type-species of Monomorium has been stated as M. minutum Mayr 
(1855), but for some unknown reason all later authors appear to have overlooked the fact that minutum 
Mayr is a junior secondary homonym of Atta minuta Jerdon (1851), which is itself a junior synonym of M. 
pharaonis (L.). 

Jerdon's short diagnosis of Atta minuta and his description of its habits leaves no doubt that its true 
identity is pharaonis. He says that 'this minute species makes a temporary nest in various situations, in an 
empty box, between the back of a book and its leaves, even among the loose pages of a book, in an empty 
shell, &c. &c. Nothing is used in its construction, a shelter from the light merely being sought for.' He also 
says that it is 'very common in the Carnatic and most of India', and that it 'appears to prefer dead animal 
matter to saccharine or vegetable products.' 

As far as I can ascertain minuta Jerdon appeared as a synonym of pharaonis for the first time in Emery 
(1892) and the synonymy is repeated in Dalla Torre (1893). Earlier Mayr (1878) had suggested that minuta 
Jerdon and vastator Smith were conspecific. Examination of the vastator type-material confirms that its 
synonymy with pharaonis by Donisthorpe (1932) was correct. Bingham (1903) included minuta Jerdon as a 
synonym of pharaonis and it is most likely that he had access to, and examined, Jerdon's now vanished 
material. 

All this serves to confirm that Atta minuta Jerdon truly belongs in Monomorium and is a valid junior 
synonym of pharaonis. This leaves M. minutum Mayr as a junior homonym in need of a replacement name. 

In the past some 17 infraspecific taxa of minutum Mayr have been described. None of these infraspecific 
names applied to southern European forms (the type-locality of minutum Mayr is in Italy) and only one, 
chinense Santschi, was described from the Palaearctic region. Other supposed infraspecific forms of 
minutum Mayr originated in the Afrotropical region, Madagascar, Sri Lanka, Java, Hawaii, Samoa, North 
America and Brasil. Examination of the available type-material of these forms and comparison of that 
material with the type-series of minutum (in NMV) leads me to conclude that only chinense, javanum 
Forel, and liliuokalanii Forel (= samoanum Santschi) belong in the same species-complex as minutum 
Mayr. The last two names were given as junior synonyms of minutum by Wilson & Taylor (1967) but I do 
not consider them conspecific and suspect that they may in fact be synonymous with chinense, which 
appears to be valid and distinct from minutum Mayr. Finally I suspect that the southern European 
populations currently referred to as minutum Mayr may in truth consist of two separate species. 

Hence none of the current infraspecific names is taxonomically available as a replacement for the junior 
homonym minutum Mayr, and I have designated the name Monomorium monomorium as a replacement 
for M. minutum Mayr. 

Note 2, authorship and date of M. antarcticum, type-species of Notomyrmex. 

Earlier catalogues such as Mayr (1863), Dalla Torre (1893), and Emery (1922) all regarded Smith (1858) 
as the author of the species-level name antarctica, but Brown (1958) and Ettershank (1966) refer the name 
to White and date it 1848. Brown gives Hutton (1881) as the authority for this date but the entry under 
antarctica in this last publication refers back only to Smith (1858). 

Smith's (1858: 167) notation of this name gives 'Atta antarctica' and is sub-headed 'Formica antarctica, 
White, Zool. Erebus & Terror, pt. 2.' The section of the 'Zoology of the Voyage of H.M.S. Erebus & 
Terror' which deals with insects has Adam White and Arthur Gardiner Butler as joint authors, and the date 
on this part is given as 1846-1874! However, the 'contents' of volume 2 indicate that the insects were dealt 
with in two sections, the first of which, pp. 1-24, was by White and is dated 1846. The second part, pp. 
25-51, was by Butler and is dated 1874. This same information is repeated in the massive review of early 
entomological literature by Horn & Schenkling (1929), who added that plates 1-6 accompanied pp. 1-24, 
which appeared in 1846 with White as author. 

Unfortunately the name antarctica in the 'Voyage of H.M.S. Erebus & Terror' publication is on page 27 
and plate 7, as Aphaenogaster antarctica, and appeared in 1874 with Butler as author. Secondary notations 
below this name include 'Formica antarctica, White Ms, tab. 7, f. 13,' and 'Atta antarctica, Smith, Cat. 
Hymenopt. Ins. 6 p. 167,' indicating that Butler was aware that the name was already extant in the 
literature and available by dint of Smith's (1858) publication. 

All this internal evidence seems to show that Smith had access to the then unpublished notes of White 
referring to insects of the Erebus & Terror voyage which had not been included in White's (1846) 



SOLENOPSIS GENUS-GROUP 289 

publication (which finally appeared in Butler, 1874). Thus by using the name Atta antarctica, and producing 
a description of the species from White's unpublished manuscript, Smith ( 1858) became the valid author of 
the name. 

Worker. Minute (TL < 1-5) to moderate (TL ca 8.0) sized monomorphic to polymorphic myrmicine ants. 
Palp formula predominantly 2,2 but counts of 5,3; 3,3; 2,3; 1,2; and 1,1 are known in some individuals or 
discrete species-groups. Mandibles with 3-5 teeth (4 is the vastly predominant count) which decrease in 
size from apex to base. Basalmost tooth sometimes reduced to a minute offset denticle. Median clypeal seta 
conspicuous. Median portion of clypeus raised, the raised section longitudinally bicarinate; the carinae 
usually distinct but sometimes reduced or blunt and rounded. Frontal carinae absent behind frontal lobes. 
Antennal scrobes absent. Antennae 10-12 segmented (most frequently 12), usually with a conspicuous 
3-segmented club but in some the club 4-segmented or not clearly defined; club never of 2 segments. Eyes 
present, usually conspicuous but reduced in some ; reduced to a single ommatidium in the fossulatum-group 
(Fig. 94). Eyes situated at or in front of the midlength of the head side. Metapleural glands of moderate 
size, never enormously hypertrophied. Metapleural lobes usually small and rounded. Metanotal groove 
present, commonly impressed. Propodeal dorsum usually unarmed and rounding into the declivity, some 
individuals or whole species-groups with the propodeum angulate, denticulate, or with short angular 
lamelliform projections; developed propodeal spines extremely rare. Propodeal spiracle usually circular 
and located at about the midlength of the sclerite, rarely slightly behind the midlength; the spiracle oval to 
slit-shaped in the scabriceps-group (Fig. 33). Fore coxae larger than middle and hind coxae but not grossly 
enlarged. Petiole pedunculate anteriorly, the petiolar spiracle usually close to or at the node, only rarely 
close to the midlength of the peduncle (scabriceps-group. Fig. 33, and some Australian species). Petiole 
node generally subconical to cuneate in profile, and narrowly rounded above. Petiolar peduncle with a 
small anteroventral process, only rarely the process vestigial or lacking. Sting strong to very feebly 
developed, in many linear-subspatulate apically but lacking lamelliform appendages at an angle to the long 
axis of the sting. 

Female. Larger than conspecific worker, sometimes very much larger. Head not disproportionately small 
in comparison to alitrunk, the HW usually equal to or greater than the maximum width of the mesoscutum, 
only rarely slightly narrower. Usually alate and with a full complement of flight sclerites but numerous 
species with apterous to extremely ergatoid females, these wingless forms showing a finely stepped 
morphoclinal reduction in size and number of alitrunk sclerites (Figs 27-30). A few species with 
worker-female intergrades. Characters as worker but eyes larger and sometimes slightly behind the 
midlength of the sides. Ocelli present except in some extreme ergatoids. Short flattened propodeal spines 
occur in a few ergatoids. On the forewings of alates the radial cell is always open and cross-vein r-m absent. 
Cross-vein m-cu is conspicuous in a few groups (Figs 18, 19) but is usually absent. Species of the 
scabriceps-group show its disappearance (Figs 19-21) and sometimes an individual may have m-cu present 
on one forewing but absent from the other. In small or minute species of all groups cross-vein cu-a tends to 
vanish (Figs 23, 24). Primitively all veins are tubular and strongly sclerotized (Figs 18-21) but in most 
groups the veins are predominantly depigmented and flattened, or reduced to vestigial lines (Figs 22, 23). 
In the last case R + Rs and 2r plus the distal portion of Rs usually remain broader and more strongly 
sclerotized than the remaining veins (Figs 22, 23). Axillae frequently large and almost meeting at the 
midline, in some groups the axillae partially or wholly fused and stretching as a band across the entire 
dorsum. Mesoscutum and scutellum never abutting, always separated by the axillae or, where the axillae 
are separated mid-dorsally, by a broad impression. 

Male. Usually the same size as or a little smaller than the conspecific female, generally much larger than 
the worker but in the scabriceps- and destructor-groups the males are very small indeed. Head width at 
maximum about equal to the width of the mesoscutum except in the two groups just mentioned, where the 
head is disproportionately small and much narrower than the mesoscutum. PF as in workers. Mandibles 
with 1-4 (usually 3-4) teeth, the basalmost sometimes reduced to a minute denticle. Median clypeal seta 
conspicuous, median portion of clypeus not bicarinate. Antennae with 11-13 segments, not clavate 
apically. Scape cylindrical to globular, first funicular segment cylindrical to globular (Figs 25, 26). Eyes 
large, usually situated near the midlength (Fig. 25) but in the scabriceps- and destructor-groups situated 
anteriorly, abutting the clypeus (Fig. 26). Ocelli conspicuous, turreted in some groups. Parapsidal furrows 
distinct to vestigial. Notauli usually absent, only rarely present. Mesoscutum frequently with a V-shaped 
unsculptured or more weakly sculptured area anteromedially. Venation as alate female. Axillae small and 
separated by a transverse impression, sometimes fused to scutellum and more rarely also fused to scutum. 
Axillae extend as a band across the dorsum in scabriceps- and destructor-groups. Male frequently more 
strongly sculptured than conspecific female or worker. 



290 B. BOLTON 

Monomorium is a large and extremely diverse genus which contains at present some 300 valid species, of 
which about half occur in the Afrotropical zoogeographical region. The estimate of the world fauna is very 
much a guess as the species of most zoogeographical regions have never been revised or subjected to any 
synthesizing taxonomic treatment. As the genus is defined here the vast majority of Monomorium species 
inhabit the Old World, particularly the tropics. Very few endemic species occur in North America 
(DuBois, 1986), and even fewer in the neotropical region where Monomorium is mostly replaced by an 
extensive Solenopsis fauna (Kempf, 1972). The main centres of speciation of Monomorium include Africa 
and Australia, with secondary centres in the Oriental region (Bingham, 1903) and Madagascar. The 
Malagasy fauna is particularly interesting as it contains some small endemic species-groups, one of which 
(with two indeterminate species) shows the highest and hence most primitive PF count (5,3) yet 
encountered in the genus. In general the species-groups of Monomorium are not restricted to a single 
zoogeographical region but tend to be widely distributed. However, some small specialized groups have a 
much more restricted range. Most species-groups remain to be defined on a world-wide basis. The groups 
occurring in the Afrotropical region, revised below, are so defined, but the large and fascinatingly diverse 
Australasian fauna contains a good number of endemic species-groups which await accurate delineation. 
After Africa Australia contains the most diverse and widely radiated fauna of the genus and a taxonomic 
study of it is long overdue, especially in the light of the fact that the Neotropical genera Nothidris and 
Antichthonidris appear to be nothing more than isolated fractions of this fauna. 

Workers of Monomorium show a striking morphological diversity from group to group but within 
species-groups tend to be relatively uniform in structure. The most strongly modified forms include the 
large granivores of the scabriceps-group , but these constitute only a small fraction of the fauna, most 
species of which are scavengers or active predators. Females for the most part share the characters 
exhibited by the workers. In some groups, particularly the salomonis- and monomorium-groups, there is a 
marked tendency for the females to become apterous and ergatoid. It has been postulated (Bolton, 1986b) 
that this phenomenon is associated with a shift in dispersal strategy from mating flight followed by claustral 
nest founding to autoparasitism followed by colony fission. Males remain poorly known in the genus but for 
the most part present a fairly uniform habitus except in the scabriceps- and destructor-groups where they 
have convergently come to resemble the males of Solenopsis. 

Monomorium contains some of the world's most widely distributed and successful tramp-species, 
including the cosmopolitan pharaonis (L.) and floricola (Jerdon), the pantropical destructor (Jerdon), and 
the Old World tropical latinode Mayr, subopacum (Smith), and talpa Emery. 

Apart from the references given above, recent taxonomic works on Monomorium at species-level are 
very sparse. Mention may be made of Wilson & Taylor (1967) for the Polynesian fauna, Baroni Urbani 
(1964a, 19646, 19686) for the Italian fauna, Bernard (1968) for the west European fauna, Brown (1958) for 
the fauna of New Zealand, Collingwood (1978) for the fauna of the Iberian Peninsula. Older synoptic 
studies, now rather outdated but still retaining some value include Arnold (1916), Bingham (1903), Emery 
(1908a, 19086), and Santschi (1936). 

The genus-level synonyms of Monomorium 

The current genus-level synonymy of Monomorium is extensive, including some 22 names at the present 

time. Discounting nomina nuda these names consist of a number of supposed oddities which were 

originally described as separate small genera, and a welter of moderately to extremely poorly defined 

subgenera which were described in the first quarter of this century. In terms of the species-group concept 

employed in this paper the various genus-level synonyms are dispersed as follows among the groups. 

Species-group in this paper. Genus-level synonyms of Monomorium applicable to that group. 

M. salomonis-group Epixenus, Paraphacota, Wheeleriella, Xenhyboma, Xeromyrmex. 

M. scabriceps-group Holcomyrmex, Trichomyrmex . 

M. destructor-group Equestrimessor, holcomyrmex, Parholcomyrmex. 

M. fossulatum-group Ireneidris, Syllophopsis . 

M. monomorium-group Corynomyrmex, Epoecus, Lampromyrmex, Mitara. 

M. forcipatum-group Chelaner, Notomyrmex. 

M. falcatum-group Schizopelta. 

M. rothsteini-group Protholcomyrmex . 

Phacota, included by Ettershank (1966) as a synonym of Monomorium, is here returned to its previous 
status as a separate genus, for reasons given under its discussion, p. 281. 

Baroni Urbani (1964a: 50) described a genus Xenoaphaenogaster based on a single worker discovered in 
a nest of Aphaenogaster pallida (Nylander). The holotype and only known specimen of the type-species, X. 
inquilina Baroni Urbani, has since been lost. In the original description Baroni Urbani placed 



SOLENOPSIS GENUS-GROUP 291 

Xenoaphaenogaster in the tribe Solenopsidini as it was then understood, close to Monomorium. Later 
Brown (1973) treated the name as a provisional synonym of Monomorium, a position reiterated by 
Krombein et al. (1979). This placement is certainly incorrect and X. inquilina is not to be associated with 
Monomorium or its close relatives. In my opinion, based on the original description and figures, the 
now-vanished holotype of X. inquilina may well have been a minor worker of Pheidole pallidula 
(Ny lander). I hereby provisionally synonymize X. inquilina under P. pallidula, so that the genus-level 
name Xenoaphaenogaster falls into the synonymy of Pheidole. 

Genus-level names applicable to the Monomorium salomonis-group. 

Wheeleriella Forel (1907c). 

Forel (1905) erected the name Wheeleria santschii for a monomoriine inquiline female found with M. 
salomonis in Tunisia. He observed that it was 'probably a parasitic derivative of the genus Monomorium.' 
Later Forel (1907c) noted that the genus-level name Wheeleria was preoccupied, and proposed Wheeler- 
iella as a replacement. 

In the following two decades the names of four more inquilines were added to Wheeleriella. These 
included wroughtoni Forel (1910a) from India (which is incidentally a junior homonym of M. wroughtoni 
Forel (1902), a replacement name is proposed below), and adulatrix Santschi (19136), rufescens Santschi 
(19266), and insidiosa Santschi (19266), all from Tunisia. The last three names were all treated as 
infraspecific forms of santschii by Santschi (19266) and the present survey regards them all as very minor 
variations within the species-limits oisantschii, and hence junior synonyms of that name. 

All samples known to the present have been found at the entrances to nests or within nests of 
salomonis-group members. According to Forel (1906) and Santschi (19136) females of santschii approach 
the host nest and wait for a while at the entrance. They are soon accepted by the host workers and gain 
entry to the nest. Shortly thereafter the host workers kill their own reproductive female and adopt the 
inquiline, which goes on to lay numerous eggs. These produce only females and males; the worker caste has 
been lost. 

The name Wheeleriella was summarily synonymized with Monomorium by Ettershank (1966), without 
further comment. Whilst agreeing totally with Ettershank's conclusion it must be pointed out that the 
former members of Wheeleriella are, morphologically, only very slightly modified from other members of 
the salomonis-group, and that the five names formerly included in Wheeleriella represent at most two, and 
possibly even only one, valid species. 

The females are very obviously specialized members of the salomonis-group in which the eighth 
funicular segment is enlarged to form a 4-segmented club and the occipital margin of the head has become 
strongly concave. The same modification of the head occurs weakly in the males, but their funiculi are 
normal for the salomonis-group. In both sexes the mesoscutum is flattened and bulges forward anteriorly 
so that it overhangs the pronotum, and in females the petiole and postpetiole nodes are anteroposteriorly 
compressed. These last two characters occur, though not as strongly developed, elsewhere in the 
salomonis-group. For example, the female of afrum Andre shows modifications in structure that are 
surprisingly like those of santschii. Unlike santschii, however, afrum retains a worker caste. I suspect that 
the female of afrum may be a temporary social parasite. The two species presently recognized, which 
formerly constituted Wheeleriella, are as follows. 

Monomorium santschii (Forel) 

Wheeleria santschii Forel, 1905: 171. Holotype female (dealate), Tunisia: Kairouan, 19.viii. 1903 (F. 

Santschi) (MHN) [examined]. 
Wheeleria santschii Forel; Forel, 1906: 51. [Descriptions of female and male, and notes on biology.] 
Wheeleriella santschii (Forel) Forel, 1907c: 145. 
Wheeleriella adulatrix Santschi, 19136: 229. Holotype female (dealate), Tunisia: Kairouan, 22.x. 1913 

(F. Santschi) (NMB) [examined]. Syn. n. 
Wheeleriella santschii st. insidiosa Santschi, 19266: 233. Syntype females, males, Tunisia: Cheri-chera, 

25.x. 1925 (F. Santschi) (NMB; MCZ) [examined]. Syn. n. 
Wheeleriella santschii var. rufescens Santschi, 19266: 233. Syntype females, males, Tunisia: Kairouan 

(F. Santschi) (NMB) [examined]. Syn. n. 
Monomorium santschii (Forel) Ettershank, 1966: 92. 

Host: Monomorium salomonis (L.). Distribution: Tunisia. 



292 B. BOLTON 

Monomorium effractor nom. n. 

Wheeleriella wroughtoniV or t\, 1910a: 7. Syntype females, males, India: Poona, 24. v. 1890, and 7. iv. 1891 
(R. Wroughton) (BMNH; MHN) [examined]. (Junior secondary homonym of Monomorium wrought- 
o/i/Forel, 1902:209.) 

Monomorium wroughtoni (Forel, 1910a) Ettershank, 1966: 93. 

Host: Monomorium indicum Forel. Distribution: India. 

Epixenus Emery (1908a). 

Further to Brown & Wilson's (1957) extensive discussion of Epixenus and its subsequent synonymy with 
Monomorium it has become even more obvious that their conclusions were correct, and that Epixenus 
consisted of nothing more than a loose assemblage of salomonis-group females which happen to be 
apterous or ergatoid. The characters formerly invoked to differentiate Epixenus from Monomorium rested 
on the ergatogyny of these females and their supposed workerless parasitic lifeway , and on the observation 
that in at least the earlier described females the petiolar and postpetiolar nodes were broader and narrower 
than was 'normal' in Monomorium. 

During this present survey of salomonis-group members numerous females have been examined, and 
the supposedly specialized form of petiole and postpetiole confirmed as being non-existent in reality, as 
was earlier pointed out by Brown & Wilson (1957). Members of Monomorium exhibit a range of petiolar 
and postpetiolar forms, the same shapes sometimes being independently derived in different species- 
groups and the range of node form within some groups being very variable. The salomonis-group is a case 
in point as the supposedly specialized nodes seen in the species which formerly made up Epixenus are in 
reality part of a continuous variation which spans the group, some but not all of the former Epixenus 
species merely being at the extreme end of the varietal range. One species originally described in Epixenus, 
guineensis Bernard, was incorrectly placed there because its author relied upon node shape. In this case the 
node shape was acquired by parallel development in a radically different small species-group confined to 
sub-Saharan Africa, see p. 425. 

As for the apterous or ergatoid females supposedly characteristic of Epixenus, similar or less strongly 
ergatoid forms are also found in venustum (Smith), opacior Bolton, minor Stitz, damarense Forel, 
dichroum Forel, rufulum Stitz, hesperium Emery, medinae Forel and pallidum Donisthorpe of the 
salomonis-group. In all of these the wings have never been developed but in some the usual full 
complement of alitrunk sclerites is present, though reduced in size. In others the mesoscutum, scutellum 
and axillae are partially or wholly fused (Figs. 27-30). Such forms constitute stations in a continuous 
morphocline between the usual winged females of the salomonis-group and the ergatoid females which 
formerly made up Epixenus (Bolton, 1986ft). 

Concerning the supposed parasitic workerless lifeway of Epixenus species, this was based on speculation 
from the outset and the speculation was rendered dubious by Bernard's (1955) description and discussion 
of algiricus Bernard workers. The parasite hypothesis has recently been utterly discredited by Tohme & 
Tohme (1979) who showed that the ergatoid females are not parasites but are the usual reproductive forms 
of the workers with which they are associated. To replace the parasite hypothesis I suggested (Bolton, 
1986ft) that like pharaonis these species utilize autoparasitism followed by polygyny and colony fission as 
their means of dispersal. 

The only disconcerting aspect of the Tohme & Tohme (1979) paper was their retention of the name 
Epixenus, despite the fact that their study destroyed one of the major characters invoked to isolate the 
genus. That they were unaware of Brown & Wilson's (1957) synonymy, or of Ettershank's reiteration of it, 
is apparent as both works are omitted from their references. 

In summary then, Epixenus is a straight synonym of Monomorium and all its included species except 
guineensis are referable to the salomonis-group. The species in question are those dealt with by Brown & 
Wilson (1957), and the following. 

Monomorium grassei (Tohme & Tohme) comb. n. 

Epixenus grassei Tohme & Tohme, 1979: 1088, figs 1-4. Syntype workers, females, males, Lebanon: 
Turbol, central Bekaa, 23.X.1977 (Tohme & Tohme) (MNHN). 

Monomorium syriacum (Tohme & Tohme) comb. n. 

Epixenus syriaca Tohme & Tohme, 1979: 1100, fig. 7. Syntype workers, female, Syria: Markab, south of 
Banias, 10 m, 10.iv.1974 (Tohme & Tohme) (MNHN). 



SOLENOPSIS GENUS-GROUP 293 

Monomorium libanicum (Tohme & Tohme) comb. n. 

Epixenus libanicus Tohme & Tohme, 1979: 1103, fig. 8. Syntype workers, female, Lebanon: Mt Liban, 
Laklouk, 1200 m, 6.iv.l966 {Tohme & Tohme) (MNHN). 

Paraphacota Santschi (1919a). 

This genus was based on three males taken at light at Biskra in Algeria, which Santschi (1919a) described 
as Paraphacota surcoufi. He believed that Paraphacota was very close to 'subgenus Xeromyrmex Em., of 
which it is probably a parasitic derivative.' His only character differentiating Paraphacota from the 
salomonis-group of Monomorium (i.e. , the old subgenus Xeromyrmex, in part) was the great elongation of 
the genital parameres in the former. 

Later the same year Santschi (1919c) described Paraphacota cabrerai from the Canary Islands, and a 
couple of years after that he added a third form, obscuripes Santschi (1921c), also from the Canary Islands. 

By the time of his review of some members of the salomonis-group, Santschi (1927) had realized that 
these males with elongate parameres were in fact referable to Monomorium subopacum or its closest 
relatives. He sank obscuripes as a straight synonym of subopacum and relegated surcoufi (the type-species 
of Paraphacota) and cabrerai to varietal status under subopacum. By doing this he effectively synonymized 
Paraphacota with Monomorium, by shifting all the contents of the former, including its type-species, to the 
latter, a different and senior genus. Remarkably, instead of acknowledging the synonymy, and perhaps in a 
misguided attempt to retain the name Paraphacota, he designated (Santschi, 1927: 245) a completely 
different species {Phacota noualhieri Emery) as a replacement type-species for Paraphacotal 

Taxonomically this is both naive and unacceptable as the type-species of Paraphacota can only be 
surcoufi (by monotypy), and Santschi's (1927) redesignation is utterly invalid. Unfortunately Ettershank 
(1966) picked up this ridiculous redesignation and perpetuated the error, which was again repeated in 
Bolton (1973). The correct apellation and synonymy of Paraphacota is given in the synonymic synopsis of 
Monomorium, above. For discussion of Phacota noualhieri, now included in the M. salomonis-group, see 
p. 282. 

Comparison of the male types of the various names formerly included in Paraphacota with the males of 
other salomonis-group species indicates that the Algerian surcoufi and Canary Islands cabrerai match the 
males of Monomorium subopacum from localities as far apart as Egypt and the Cape Verde Islands; these 
names are treated as direct synonyms of subopacum (p. 360). The holotype male of obscuripes, from the 
Canary Islands, also resembles subopacum males very closely indeed but has the appendages and genital 
parameres much darker. It is also treated here as a synonym of subopacum but more material of this form is 
required for study and its status may be changed when it is better known. 

Wheeler (1927a) suspected that cabrerai may be the male of medinae (= mystes), a suggestion repeated 
by Espadaler (1982). To the present no males have been found in direct association with medinae so this 
remains merely a supposition in need of further investigation. If the male of medinae, or the other endemic 
Canary Island species hesperium, does have elongate narrow parameres like those of subopacum (which is 
also present in the Canary Islands) then I am more inclined to suspect obscuripes of being that male, as the 
male of cabrerai seems indistinguishable from that of subopacum. 

Xenhyboma Santschi (1919c). 

Santschi (1919c) described a strange ant species, Xenhyboma mystes, from a single female found at 
Teneriffe in the Canary Islands. He assumed that it was a parasitic form and stated that it was related to 
Monomorium and Epixenus; the latter now known to be the name earlier applied to a number of species of 
the Monomorium salomonis-group in which the females are apterous or ergatoid (see above). 

The taxonomic history of mystes since then, and the speculations about its biology and identity, have 
been neatly summarized by Espadaler (1982), who has shown that X. mystes is in fact the normal 
reproductive female of the Canary Islands endemic species Monomorium medinae Forel, confirming the 
previous suggestion by Kutter (1972) that such was the case. Ettershank (1966) had earlier provisionally 
synonymized Xenhyboma under Monomorium but had given no discussion of his reasons for doing so. 
Espadaler's (1982) study conclusively proved the synonymy. 

Espadaler (1982) also mentioned Wheeler's (1927a) suspicion that mystes may be the female of 
Paraphacota cabrerai, also described from Teneriffe and based on a single male specimen. I am inclined to 
disagree with this as the males formerly placed in the spurious genus Paraphacota all seem synonyms of 
Monomorium subopacum, another species fairly common in the Canary Islands and also very widespread 
indeed around the Mediterranean. This opinion is of course open to revision, but as males directly 
associated with medinae (= mystes) remain unknown speculation is all that is presently possible. 

Thus medinae is yet another salomonis-group species which has developed an ergatoid female along 



294 B. BOLTON 

with, among those species where the female is known, venustum, pallidum, opacior, rufulum, dichroum, 
damarense, minor, hesperium, and those species formerly included in Epixenus. In the light of recent works 
by Bernard (1955), Tohme & Tohme (1979) and Espadaler (1982) the old tacit assumption that all these 
forms are socially parasitic, often without the slightest evidence that such was the case, must be discarded. 
A more likely means of colony spread in these species involves the development of autoparasitism followed 
by polygyny and colony fission (Bolton, 1986ft). In this system the apterous or ergatoid females mate within 
the parent colony, or return to it immediately after mating outside. At some time after this the now 
polygynous nest undergoes fission, with some of the newly mated females leaving along with some workers 
to commence a new colony elsewhere. 

In the salomonis-group such apterous or ergatoid females retain the basic characters of the group but the 
alitrunk becomes very specialized by reduction of the flight sclerites. In some the alitrunk retains most or all 
flight sclerites though in a somewhat reduced form and the wing-roots are sealed or overgrown with cuticle, 
or never developed. Wings and tegulae are of course lacking. From such forms more advanced modifica- 
tions include the reduction in size of the mesoscutum so that the pronotum comes to constitute a part of the 
dorsal alitrunk, the fusion of the mesoscutum, scutellum and axillae into a single sclerite which may then be 
reduced in size, and the development of a saddle-shaped outline to the mesoscutum plus scutellum, which 
is depressed centrally in its outline when viewed in profile (Bolton, 1986ft). 

Another salomonis-group species originally described from the Canary Islands, hesperium, was re- 
garded by Espadaler (1982) as possibly being a synonym of medinae. Workers of the two are indeed close, 
being separated primarily by the presence of fine reticulate-punctate sculpture on the meso- and 
metapleura in medinae and its absence in hesperium, where the sides of the alitrunk are free from sculpture 
and glassy smooth. Females of the two are, however, very different. Unfortunately workers apparently 
matching the holotype of hesperium are also found on the Cape Verde Islands but the apterous females 
associated with this series, figured by Bolton (1986ft) as hesperium, appear different from the apterous 
females referred to hesperium and described by Espadaler & Agosti (1985) from the Canary Islands. Hence 
a third species appears to be involved and only a critical re-examination of the holotype worker of 
hesperium, in the presence of the hesperium-\\ke workers from the Canary Islands and Cape Verde Islands 
series, may be able to solve the problem. Nevertheless, I am inclined to believe that Espadaler & Agosti 
(1985) have the female associated correctly and that the Cape Verde series (in BMNH) represents an 
undescribed species. 
The two described species involved are as follows. 

Monomorium medinae Forel 

Monomorium medinae Forel, 1892ft: 454. Holotype worker, Canary Islands: Teneriffe, Laguna 

{Medina) (MHN) [examined]. 
Xenhyboma mystes Santschi, 1919c: 405, fig. 2. Holotype female, Canary Islands: Teneriffe, Laguna, 

10. iv. 1918 (A. Cabrera y Diaz) (NMB) [examined]. [Synonymy by Espadaler, 1982: 112.] 

Definitely associated male of the species remains unknown. 

Monomorium hesperium Emery 

Monomorium hesperium Emery, 1895a: 298, fig. 3. Holotype worker, Canary Islands: no loc. (Alluaud) 
(MCSN) [examined]. 

Female described by Espadaler & Agosti (1985), male remains unknown. 

Xeromyrmex Emery (1915). 

This subgenus of Monomorium, as defined by Emery (1915) with salomonis as type-species, was given no 
formal diagnosis except in the prototype key to subgenera which Emery compiled in that publication and 
later expanded (Emery, 1922). The separation of the subgenus depended on unsatisfactory characters 
relating to relative dimensions of antennal club segments and to number of antennal segments. This led 
Forel (1917) in his synopsis of formicid classification, to complain that subgenus Xeromyrmex was 
insufficiently defined. Despite this warning of the weakness of the system Emery (1922) expanded his key 
to include several more names and the key was reproduced, with some rearrangement, by Wheeler (1922). 
This repetition of the system somehow served to invest it with an apparent utility and stability which in 
truth was utterly lacking. 

Santschi (1930ft) was unhappy about the Emery- Wheeler classification based on club segments and he 
pointed out that pharaonis and its allies, as then understood, fell between the subgenera Monomorium (s. 



SOLENOPSIS GENUS-GROUP 295 

str.) and Xeromyrmex as then defined. He did not resolve the problem and later (Santschi, 1936) was still 
using Xeromyrmex despite the fact that all the insecurity of the system was still present. The problem of 
defining Xeromyrmex was not resolved but rather was sidestepped, in that newly described species 
recognizably close in habitus to salomonis or its immediate allies were placed in Xeromyrmex. Others 
which did not have the habitus of salomonis were scattered in the remaining subgenera or had new 
subgenera erected to contain them. 

Arnold (1944) criticized the use of relative dimensions of club segments to define the subgenera of 
Monomorium and proved his case by carrying out careful measurements on a number of species. He 
concluded that, 'the differences are in some cases imaginary, or alternatively, that Emery has placed some 
species in the wrong subgenera or that the subgenera cannot be defined with any exactitude.' It only 
remained for Ettershank (1966) formally to synonymize Xeromyrmex under Monomorium to bring the 
history of this subgeneric name to a close. 

My interpretation of the history of Xeromyrmex is that initially Emery recognized salomonis and its 
immediate allies by habitus alone, and then cast about for characters to define the group and isolate it from 
other groups of Monomorium . Failing to find any obvious character or combination of characters to delimit 
the group he somehow ended up using the very vague and inaccurate system based on relative dimensions 
of antennal club segments, which did not work too well even on the relatively few species then known. But 
the system, once proposed, became self-perpetuating by means of its inclusion in the classical studies of 
Emery (1922) and Wheeler (1922). The system was criticized thereafter but nothing better was put 
foreward. Unfortunately the monomoriine fauna known in 1915-22 was only a fraction of that known 
today and, as time went by, species added to the various subgenera of Monomorium stretched the 
credibility of the system past breaking point, either by failing to fit the pre-existing categories, or by 
overlapping them and thus occluding the supposed differences. 

The present concept of the salomonis-group (p. 329) is based on the core-species of the now defunct 
Xeromyrmex, with, however, a good number of exclusive and inclusive changes from the 1922 concept put 
foreward in the Emery-Wheeler joint classification. At present the salomonis-group includes those species 
immediately related to salomonis, plus the small complex of species surrounding pharaonis, and those 
forms once regarded, rightly or wrongly, as parasites belonging to the genera Wheeleriella, Paraphacota, 
Xenhyboma and Epixenus, which names are strictly synonyms of the Salomon w-group within Monomor- 
ium. Excluded are the species now constituting the setulife rum-group (p. 365) and a number of other odd 
species previously wrongly included in this group. 

Genus-level names applicable to the Monomorium scabriceps-group 

Holcomyrmex Mayr (1878). 

Originally described as a distinct genus and so treated by earlier authors such as Bingham (1903). Emery 
(19086) recognized the former Holcomyrmex members as belonging to Monomorium and later the name 
was used as a subgenus within Monomorium by Forel (1917), Emery (1915, 1922) and Wheeler (1922). It 
continued as such until it was synonymized with Monomorium by Ettershank (1966). 

During the late 1800s several species were added to the scabriceps-group, as Holcomyrmex, which are 
now regarded as members of the destructor-group or other related groups. The process of removing these 
species from the scabriceps-group had mostly been completed by the time of Emery's (1922) catalogue , but 
a couple of names wrongly included there by him are transferred elsewhere in this study (p. 321). 

For separating the scabriceps-group from other groups of Monomorium, much emphasis was laid in the 
past on the structure of the antennae in the workers and males. In the former the funiculus was regarded as 
lacking an apical club (Fig. 31) and in the latter was described as having a short scape, globular first 
funicular segment and the remainder flagelliform (Fig. 26). Whilst the description of the male antenna is 
accurate that of the workers (and females) should be modified so that it is understood that the apical 
funicular segments gradually increase in size apically or the terminal 3-4 segments form a weak club. The 
antennal characters alone cannot be used to separate Holcomyrmex as the worker funiculus grades into the 
clavate form usually seen in Monomorium and the male antenna is indistinguishable from that seen in the 
destructor-group . 

Despite this the presently recognized members of the group (p. 321) form, in the workers, a fairly 
distinctive collection of relatively large polymorphic species which range through the Oriental region and 
also occur in the Mediterranean Palaearctic and the sahelian zone of the Afrotropical region. All are 
granivorous and are characterized by their near-vertical slit-like or elliptical propodeal spiracles and the 
position of the petiolar spiracle, which is close to the midlength of the peduncle rather than at the level of 
the anterior margin of the node or within the body of the node. These features separate the scabriceps- 
group from most other Monomorium and I suspect may make this group the strongest candidate for 



296 B. BOLTON 

isolation as a separate genus. Unfortunately the known males remain indistinguishable from those of the 
destructor-group and in the workers all characters except the shape of the propodeal spiracle show 
intermediates or near-duplicates in members of the destructo /--group. 

That the scabriceps-group and the destructor-group are extremely closely related is very evident, but I 
can find no way of isolating the two together to form a genus-level taxon except for the form of the male , but 
even here males are known which apparently form morphological intermediates between the characteristic 
salomonis-group male and those of the scabriceps- and destructo r-groups. Much of the distinctive habitus 
of the scabriceps-group stems from their adoption of a granivorous diet and they have convergently come to 
resemble, in general aspect, other granivorous taxa such as Messor Forel, Pogonomyrmex Mayr, and the 
Tetramorium solidum-group . Elsewhere within Monomorium, the granivorous falcatum-group and to a 
lesser extent the rothsteini-group of Australia also resemble the scabriceps-group in habitus but lack the 
propodeal spiracular form characteristic of the scabriceps-group. These Australian groups and the 
scabriceps-group are analysed as convergently similar rather than as divergent members of a single parent 
group. 

For the present then, only the shape of the propodeal spiracle in the workers can be cited as an 
apomorphic character which will isolate the group from other Monomorium species. I consider this 
character to have significance only at species-group level and confirm Ettershank's (1966) synonymy of 
Holcomyrmex under Monomorium. 

Trichomyrmex Mayr (1865). 

Ettershank (1966) examined the holotype female of Trichomyrmex rogeri Mayr, the type-species and 
only member of the genus. He found it to be a member of the scabriceps-group, in the sense of his 
publication, which includes the scabriceps-group and destructor-group of the present study. A revision of 
the Oriental regional fauna of these groups will probably show rogeri as the senior synonym of a known 
species of the scabriceps-gro up, as constituted here, as Mayr (1865: 19) gives its TL as 11-0. 

Genus-level names applicable to the Monomorium destructor-group. 

Parholcomyrmex Emery (1915). 

Parholcomyrmex, also misspelled as Paraholcomyrmex later in the same publication, was erected as a 
subgenus of Monomorium to contain those species previously regarded as Holcomyrmex but which had 
a relatively more strongly defined antennal club. In the publication Emery (1915) only nominated a 
type-species, gracillimum (now a synonym of destructor), but in his later catalogue Emery (1922) gave a 
good idea of the species which he had in mind when nominating this taxon. 

Beside his type-species he included destructor, dispar (now a synonym of oscaris) and their synonyms, 
the then infraspecific names mayri and robustior which are now regarded as valid species within the group, 
and santschianum, which later became the type-species of holcomyrmex . The remaining names which he 
included, australe, havilandi, and voeltzkowi, are now referred to different species-groups {salomonis- 
group, setuliferum-group and latinode-group respectively). The subgenus as envisaged by Emery was not 
challenged until it was synonymized by Ettershank (1966). 

This group of species, based on the direct relatives of destructor (= gracillimum) and excluding those 
noted above and those which must be excluded from Wheeler's (1922) Afrotropical catalogue, is here 
termed the destructor-group. In Ettershank (1966) species related to destructor were included in an 
expanded scabriceps-group, probably because their males are identical and very distinctive. However, 
specializations in the female castes differ consistently between the two groups and they are regarded here 
as separate, though they probably shared a common ancestor which may have looked something like the 
existing M. santschianum (see holcomyrmex below). 

The characteristic form of male seen in the destructor-group and scabriceps-group (Fig. 26) is also found 
in holcomyrmex, and a male intermediate between this form and that typical of the salomonis-group (Fig. 
25) is seen in chobauti, formerly type-species of Equestrimessor . Workers of the destructor-group show 
most affinity with those of the scabriceps-group (Figs 31-35, 41) but are also similar in many respects to the 
members of the setuliferum-group. Thus the destructor-group, even in its present restricted form, is not 
deserving of genus-level taxonomic status and Ettershank's (1966) synonymy is confirmed. 

holcomyrmex Santschi (1917). 

Added as a post-script to a paper on new ants from southern Africa, Santschi's (1917) proposal of 
holcomyrmex as a subgenus of Monomorium was an exercise in casual systematics which followed the 
philosophy that any slightly aberrant ant must be worth a generic or subgeneric name, even if the 
peculiarity is restricted to a single caste. He merely stated that the worker of M. santschianum (= santschii) 



SOLENOPSIS GENUS-GROUP 297 

had monomorphic workers and a 4-segmented antennal club, and thus merited a special name, separate 
from Parholcomyrmex (the destructor-group) . Santschi (1911) had already described the male of the 
species, which matches the form of male seen in the destructor- and scabriceps-groups, but this was 
overlooked at the time of erection of Isolcomyrmex. 

In point of fact, the workers of santschianum show a remarkable combination of destructor-group and 
scabriceps-group characters. Santschi's emphasis on the monomorphic worker condition is irrelevant as the 
destructor-group species emeryi and robustior are also monomorphic. The presence of a 4-segmented club, 
though useful in diagnosis at species-level, is not of great significance either, as it occurs, though weakly 
developed, in some members of the scabriceps-group and even convergently in a couple of salomonis- 
group species. 

As for the true position of santschianum, the very specialized and highly characteristic male firmly allies 
the species with both the destructor- and scabriceps-groups. However, a review of the worker characters 
implies that santschianum is a specialized member of the destructor-group as it has a circular propodeal 
spiracle rather than the elliptical or slit-like spiracle apomorphic in the scabriceps-group. In other respects 
it also fits the diagnosis of the destructor-group (p. 322) except for having tridentate mandibles (the minute 
offset basal denticle having disappeared) , very large eyes and a 4-segmented antennal club. The position of 
the eyes, though not their size (0.34 x HW), and the club are duplicated in some members of the 
scabriceps-group. 

The distribution of characters shown by santschianum can be interpreted as indicating either that it 
represents a specialized offshoot from close to the stem where the destructor-group and scabriceps-group 
diverged, or that it is a specialized destructor-group species convergent on the scabriceps-group in several 
characters. I suspect the former to be correct as, beside the characters mentioned above, santschianum 
workers have a clypeal structure similar to the destructor-group, short scapes (SI ca. 78), and a small 
petiolar spiracle which is situated close to the node. 

When first proposed Isolcomyrmex, later variantly spelled Isholcomyrmex by Santschi (1936), contained 
only the type-species santschianum. Wheeler (1922) added the Malagasy species shuckardi Forel, which 
emphatically does not belong here. On the other hand a peculiar Indian species, aberrans Forel, until now 
placed in the salomonis-group , appears to be the closest known relative of santschianum, at least as far as 
the workers are concerned (the male of aberrans remains unknown). 

Equestrimessor Santschi (1919a). 

Santschi (1919a) separated two granivorous species of Monomorium, chobauti (Emery) and lameerei 
(Forel), as a subgenus Equestrimessor. Later Santschi (1936) pointed out that his original manuscript 
spelling of the name had been Equessimessor but that the spelling had been changed by the editor of the 
journal. He characterized Equestrimessor as being distinct from the subgenus Xeromyrmex (now mostly 
the salomonis-group) by the presence in chobauti and lameerei of a discoidal cell in the forewing (i.e. 
cross-vein m -cu, which closes the cell, is present; as in Figs 18, 19), the possession of a truncated clypeus by 
the workers, and the presence of a short antennal scape in the male. Both species were described originally 
in Holcomyrmex , which at that time covered both the scabriceps-group and the destructor-group . These 
were later treated (Emery, 19086) as separate species-groups, but by the time of Emery's (1922) catalogue 
both species had found their way into the salomonis-group as it was then understood. 

Although Santschi was correct to remove the two from the salomonis-group the erection of a separate 
subgenus to hold them was unnecessary as they fall neatly into the destructor-group, the core-species of 
which were at that time referred to as subgenus Parholcomyrmex . The male of chobauti is structurally close 
to those of the destructor- and scabriceps-groups, but the scape is not as short as is usually seen in these 
groups (Fig. 26), nor is the first funicular segment quite so globular. In this respect the male antennae fall 
morphologically between the form seen in the destructor-group and that characteristic of the salomonis- 
group (Fig. 25). As Santschi (1919a) pointed out, cross-vein m-cu is absent in alates of the salomonis-group 
(Fig. 22) so that there is no closed discoidal cell, but this vein is variously developed in the destructor-group 
and scabriceps-group. In some individuals of the latter m-cu may be present on one forewing and absent 
from the other (Figs 19, 21). 

Turning to the worker of chobauti, it resembles nothing so much as a large (HW ca 0-96) monomorphic 
member of the destructor-group which has its clypeus more strongly truncated medially than is usual. This 
may well be correlated with the strictly granivorous diet of this species, as may the strong psammophore of 
very long ammochaete hairs which arises on the flat ventral surface of the head. 

Genus-level names applicable to the Monomorium fossulatum-group. 

Syllophopsis Santschi (1915). 
Originally described as an Afrotropical subgenus of Monomorium and later elevated by Santschi (19216) 



298 B. BOLTON 

to generic status, Syllophopsis has since been variously treated as a subgenus of Monomorium (Emery, 
1922; Wheeler, 1922; Arnold, 1952) or as a valid genus (Santschi, 1935ft; Ettershank, 1966). It is regarded 
here as a straight synonym of Monomorium, the former members of Syllophopsis being no more than the 
Afrotropical component of the Monomorium fossulatum-group which is very widespread in the Oriental 
and Indo-Australian regions. 

Until the use of litter sampling techniques became relatively common, species referable to this group 
were considered very rare. However, the employment of such collecting methods in recent years has shown 
the Afrotropical members of the group to be much more numerous than was previously suspected. 

Ettershank (1966) retained Syllophopsis as a good genus but did not see any of the African material 
which had been referred to it. If he had it is a reasonable assumption that he would quickly have discerned 
the relationship between talpa, the commonest species of the group in the Indo-Australian region, and the 
African forms, as he had synonymized one genus-level name with talpa in his study {Ireneidris, below). 

At first glance species of Monomorium belonging to this group appear quite distinct (Figs 93, 94) as the 
workers have much reduced eyes, usually down to a single ommatidium, a very narrow posteromedian 
portion of the clypeus, and a large and strongly differentiated antennal club. The development of these 
characters is, however, paralleled to varying degrees elsewhere in Monomorium, especially in the 
hanneli-group (Figs 97, 98, and p. 425), and a species intermediate between those forms which formerly 
constituted Syllophopsis and the main mass of the genus Monomorium occurs in Madagascar. For further 
discussion see p. 420. 

Ireneidris Donisthorpe (1943a). 

Donisthorpe described this genus for a single species, /. myops, from New Guinea. Ettershank (1966) 
recognized that myops was an absolute junior synonym of the widely distributed M. talpa, and Ireneidris 
fell into the synonymy of Monomorium. M. talpa is the commonest species of the fossulatum-group outside 
the Afrotropical region. 

Genus-level names applicable to the Monomorium monomorium-gr oup. 

Epoecus Emery (1893a). 

The taxonomic history of this genus-level name has been discussed by Creighton ( 1950) who also pointed 
out that our knowledge of the life history of its single species, pergandei Emery, is unsatisfactory and 
incomplete. Much of this stems from the fact that pergandei remains known only from the type-series, 
which was collected in a nest of Monomorium minimum (Buckley) near Washington, D.C., U.S.A. M. 
pergandei is certainly a workerless inquiline, and by modern concepts is plainly a Monomorium species 
belonging to, or immediately derived from, the M. minimum-complex of the Nearctic region (referred to as 
the minimum-group by DuBois, 1986). Epoecus was synonymized with Monomorium by Ettershank 
(1966), and a lectotype was designated by DuBois (1981) who also confirmed its position in Monomorium. 

Morphologically pergandei shows some interesting adaptations, not the least of which is the marked 
similarity of habitus between the females and males, though why the sexes of this inquiline should be so 
alike is not known. Both sexes may have 11 or 12 antennal segments (each count was recorded from each 
sex in the type-series), and in both sexes the mesoscutum bulges anteriorly and overhangs the pronotum, a 
,trait paralleled by a similar development of the mesoscutum in the workerless inquilines M. santschii and 
effractor of the salomonis-group. 

Like the other workerless inquilines of the minimum-compXex, talbotae DuBois and inquilinum DuBois, 
and like hospitum Viehmeyer from outside the complex, pergandei shows reduced dentition and palp 
segmentation in the female, as follows. 



Female of: 


PF 


teeth 


antennal segments 


host species 


minimum 


2,2 


4 


12 


free living 


pergandei 


1,2 


3 


11-12 


minimum 


inquilinum 


1,2 


2 


12 


cyaneum 


talbotae 


1,1 


2 


12 


minimum 


hospitum 


unknown 


1 


12 


floricola 



Where males are known of these inquiline species they show a reduction in antennal segments from 13 to 
11 or 12, have PF as the conspecific female, and have the dental count reduced to 1 or 2 teeth. 

The evidence that pergandei parallels developments seen in other inquilines from elsewhere in 
Monomorium, and shows characters which form part of a sequence from free-living Monomorium to 
morphologically even more extreme socially parasitic species, obviates the need for a separate genus to 



SOLENOPSIS GENUS-GROUP 299 

hold pergandei, and Ettershank's (1966) synonymy is confirmed as valid. The present status of pergandei is 
as follows. 

Monomorium pergandei (Emery) 

Epoecus pergandei Emery, 1893a: cclxxvi. Lectotype female (designated by Dubois, 1981: 36) and 
paralectotype females and males, U.S.A.: Washington, D.C., in nest of Monomorium minimum (T. 
Pergande) (USNM, MCZ, MCSN) [MCSN and MCZ material examined]. 

Monomorium pergandei (Emery) Ettershank, 1966: 89; DuBois, 1986: 113. 

Corynomyrmex Viehmeyer (1916). 

Viehmeyer (1916) erected a separate subgenus of Monomorium, Corynomyrmex , for a single species 
(hospitum) based on a series of 4 females and 2 males taken from a nest of the common tramp species M. 
floricola, in Singapore. 

The dull yellowish female of this apparently workerless inquiline is small, about the same size as the 
floricola worker and distinctly smaller than the reproductive female of floricola. In most aspects of its 
morphology the hospitum female is unexceptional but the mandibles are highly specialized, showing a 
reduction in dentition which is paralleled in some other inquilines (see Epoecus, above). In hospitum the 
masticatory margin of the female mandible consists of a straight edentate proximal half and a massively 
extended distal half which projects as a relatively large single sharp tooth. The inner margin of this large 
tooth shows minute crenellations which appear to be the vestigial remains of 2 preapical teeth. On each side 
this enlarged tooth projects far across beyond the midline of the clypeus, even projecting beyond the blunt 
prominence of the median portion of the clypeus on the opposite side from its insertion. Apart from the 
mandible the head is normal for Monomorium. 

The female alitrunk in dorsal view is very narrow, much narrower than the head. The mesoscutum is 
somewhat reduced but parapsidal grooves are still present. Wing remnants illustrate that the females are 
alate when virgin. 

From the original description the male, which I have not seen, seems unremarkable except for the fact 
that the antennal segmentation is reduced to 12, a character shared with other inquilines in this group. Only 
a single species was ever referred to Corynomyrmex, and it is known only from the type-series. 
Ettershank's (1966) provisional synonymy of Corynomyrmex under Monomorium is confirmed here. 

Monomorium hospitum Viehmeyer 

Monomorium (Corynomyrmex) hospitum Viehmeyer, 1916: 133. Syntype females and males, Singapore: 

no. 13: 71 (H. Overbeck) (MNHU) [female examined]. 
Monomorium hospitum Viehmeyer; Ettershank, 1966: 89. 

Lampromyrmex Mayr (1868), and Mitara Emery (1913). 

Lampromyrmex was defined to hold a single small species from the Baltic Amber, which had only 11 
antennal segments. This species, originally described as L. gracillimus, was based on 4 worker specimens, 
each embedded in a separate piece of amber. When Wheeler (1915) examined this material, and much 
more, he concluded that Lampromyrmex was a synonym of Monomorium. At the same time he pointed 
out that the name of the sole Lampromyrmex species, gracillimus, became a junior homonym when 
transferred to Monomorium, and proposed mayrianum as a replacement. 

A couple of years before Wheeler's (1915) study Emery (1913) had suggested a subgenus Mitara, in 
which he placed all the Old World species of Monomorium which had 11-segmented antennae. Later he 
realized (Emery, 1922) that this subgeneric name was unnecessary as its diagnostic characters were 
identical to those given earlier for Lampromyrmex. He therefore synonymized Mitara under Lampro- 
myrmex but continued to regard the latter as a subgenus of Monomorium, rather than as a synonym of it. 

Lampromyrmex was resynonymized under Monomorium by Ettershank (1966), who pointed out that 
the antennae in Monomorium workers may have 12, 11, or 10 segments. The present study indicates that 
the reduction of antennomere count from 12 to 11 is not synapomorphic in all species-level taxa of this 
group which show the character. It has evolved independently in several discrete lineages, certainly three 
times and possibly four times in the Afrotropical monomorium-group fauna alone. Thus, as the presence of 
11-segmented antennae does not delineate a holophyletic taxon at genus or subgenus level Wheeler's 
(1915) and Ettershank's (1966) synonymies are confirmed. 

Endemic Afrotropical species-complexes within the M. monomorium-group have antennal segment 
counts distributed as follows in the worker. 



300 B. BOLTON 

Number of species with Number of species with 

12-segmented antennae. 11-segmented antennae. 
bequaerti-complex - 3 

strangulatum-complex 4 1 

ma/ata-complex 4 1 

boerorum-complex 14 7 

all other complexes all none 



Australasian genus-level names formerly associated with Chelaner. 

In his review of Monomorium and its relatives Ettershank (1966) elevated the former subgenus Chelaner to 
generic rank, including Notomyrmex, Schizopelta, and Protholcomyrmex as junior synonyms. Whilst 
agreeing with his synonymy of these names I cannot find any character or combination of characters which 
will now serve to maintain Chelaner as a genus separate from Monomorium. 

Of the diagnostic characters listed by Ettershank (1966) as separating Chelaner from Monomorium in 
female and worker castes, only the following have any apparent validity. 

Monomorium Chelaner 

PF 2,2 or 1,2. PF 2,3 or rarely 2,2. 

Propodeal spiracle not vestibulate . Propodeal spiracle vestibulate . 

Other characters which he notes are either the same in both (structure of clypeus , antennae , pedunculate 
petiole), or are part of the genus-group diagnosis (presence of median clypeal seta, open radial cell in 
forewing), or are known to occur in both (variation in propodeal shape). 

The palp formula shows overlap even though the count of 2,2 is vastly predominant in Monomorium 
whilst that of 2,3 occurs most commonly in Chelaner. The PF count and its gradual diminution, although 
useful in places to help diagnose species-groups, forms a morphoclinal reduction through the genus as a 
whole, and PF counts of 5,3; 3,3; and 1,1 are also known in Monomorium in its broad sense. 

As for the vestibulate nature of the propodeal spiracle in Chelaner species, the character seems very 
variably developed and is by no means consistent. In some species no vestibule is discernible and the 
character has no value as a generic determinant. 

Turning to the males, the only significant character noted by Ettershank (1966) was that in Chelaner the 
mesoscutum was said to have 'parapsidal furrows faint to distinct; notauli heavily impressed to faint,' whilst 
in Monomorium 'notauli and parapsidal furrows not developed.' In most Monomorium males the 
parapsidal grooves are faint to distinct and in some the notauli are vestigially present (although usually 
absent). In fact the degree of development of the notauli shows considerable overlap between the two and 
only the few Chelaner species with relatively strongly developed notauli are not duplicated in any known 
Monomorium. Thus these character states are gradient and not useful in separating genera. 

As none of the previously invoked characters can be used to separate Chelaner from Monomorium, and 
as no new consistent characters have been discovered, Chelaner (and its junior synonyms decided by 
Ettershank (1966)) has been placed in the synonymy of Monomorium. 

Whilst I cannot present a review of species-groups of the Australasian fauna formerly constituting 
Chelaner, I can point out that three fairly distinctive aggregations of species seem discernible. It is obvious 
that Australia and its nearby islands exhibit a remarkable local radiation of Monomorium and possess a 
large number of fascinatingly adapted species which are not found elsewhere in the world, although a few 
are convergently like some extralimital groups from the Oriental and Indo- Australian regions. The three 
groups outlined below are only vaguely defined and in great need of study. I am convinced that a detailed 
investigation of the Australasian fauna will allow the diagnosis of numerous small specialized species- 
groups of Monomorium which at present are concealed within a great mass of undescribed species 
and remain unrecognized. Such a study may also show that the few species presently constituting the 
weak southern Neotropical genus Nothidris are really nothing more than an offshoot of this complex 
Australasian fauna. 

The falcatum-group represents a number of specialized granivores in which the head is disproportion- 
ately large. The mandibles have 4 teeth and the PF is 2,2. The anterior clypeal margin has an extensive 
median emargination which is flanked by a pair of broad lobes or more usually teeth. Frequently a second 
pair of teeth occurs lateral to the median pair. The petiolar spiracle is at or close to the midlength of the 
peduncle. 

M. rothsteini and its allies, formerly constituting the extremely poorly defined subgenus Protholcomyr- 
mex, represents a distinct group (rothsteini-group) in which the mandibles have 3 teeth and the PF is 2,2. 
The median portion of the clypeus is reduced and not prominent, lacking teeth at the carinal apices and 



SOLENOPSIS GENUS-GROUP 301 

without laterally situated teeth. The clypeal anterior margin is broadly but shallowly concave medially. The 
petiole node is high and the spiracle situated at the node. 

Members of the falcatum- and rothsteini-groups show remarkable convergence on the non-Australian 
members of the scabriceps- and destructor-groups respectively. Both Australian groups, however, appear 
to lack the very specialized small males seen in the other groups. Apart from this/a/cafum-group workers 
lack the slit-like propodeal spiracle seen in the scabriceps-group, do not have a much reduced fourth (basal) 
mandibular tooth, lack strongly developed divergent or out-curved clypeal carinae, have the median 
portion of the clypeus prominent and have a distinct antennal club. Members of the rothsteini-group differ 
from the destructor-group as the former always has three mandibular teeth and has eyes situated at or even 
slightly behind the midlength of the sides of the head. 

The large mass of species remaining is here termed the forcipatum-group, but this will certainly be 
divided by anyone revising the fauna. In these the mandibles usually have 5 teeth and are generally smooth. 
A few species show only 4 teeth and a few have the mandibular blades sculptured. Exceptionally a series of 
workers from some species may show both 4 and 5 teeth. Based on in situ counts the PF is overwhelmingly 
2,3 though a few may be reduced to 2,2. The clypeus is bicarinate and often the carinae terminate in 
projecting denticles or teeth. 

Other characters showing notable variation include the position of the eyes, usually close to or at the 
midlength but sometimes shifted forwards. The promesonotum is usually convex but in some it becomes 
flattened or the pronotum and mesonotum may be separated by an impression. The metanotal groove is 
usually conspicuous, but is obliterated in several species and only feebly developed in many; metanotal 
cross-ribs are often obliterated on the dorsum, or are very feeble. In several strange species the propodeal 
spiracle is relatively low down on the side and in others the petiolar peduncle is very elongate. Position of 
the petiolar spiracle varies considerably, as does the shape of the petiole node, at one extreme being 
thickly nodiform and at the other flattened and almost scale-like. The work required to bring order 
to this amazingly varied mass of species will be hard, but it will also be extremely interesting and very 
rewarding. 

The Afrotropical fauna of Monomorium 

145 currently valid species of Monomorium are recognized from the Afrotropical zoogeographical region. 
The species fall into 8 groups, as follows. 



Species-group 


Number of species 


M. monomorium-group 
M. salomonis-group 


69 

48 


M. setuliferum-group 
M. fossulatum-group 
M. destructor-group 
M. hanneli-group 
M. scabriceps-group 
M. latinode-group 


8 
7 
6 
5 
1 
1 



Of the above only the setuliferum- and hanneli-groups are not found outside sub-Saharan Africa. The 
region is the main area of speciation of the monomorium- and salomonis-groups, which together represent 
over 80% of the fauna. Extralimital species of both these groups are widely distributed in other 
zoogeographical regions but, except as an introduction, the salomonis-group is apparently absent from the 
New World, the Indo- Australian region, and Australasia. Of the remainder the destructor- and fossulatum- 
groups are primarily African but have species represented outside the region , whilst the scabriceps-group is 
mainly Oriental but has one Sahelian species. The latinode-group is represented only by latinode, a 
tramp-species widely distributed around the Indian Ocean. Its affinities are not clear but appear to lie with 
the Australasian fauna of Monomorium. 

All eight species-groups dealt with in detail here are defined on a world-wide basis, but their constituent 
species are fully revized only for the Afrotropical region. Other species-groups, those not represented in 
Africa, have been examined for comparative purposes and to render the species-group definitions 
formulated here as accurate as possible. These entirely extralimital groups, of which there are several 
in Australia, Madagascar, the Oriental and Indo-Australian regions, have not been formally defined 
here as the limits of many remain vague and must await detailed taxonomic studies of the regional faunas 
involved. 

Recent ecological studies by Alan Marsh in Namibia have unearthed a large and previously almost 
unknown fauna of Monomorium. Of the 13 species which he found only four had been described. In a 



302 B. BOLTON 

paper on pitfall trapping efficiency Marsh (1984) lists three of these species by code-letters, which are now 
identified as follows. Marsh sp. A = viator, sp. B = vatranum, sp. C = alamarum. Others found in the same 
survey but not mentioned in the publication include damarense, drapenum, esharre, katir, kitectum, 
mantazenum , marshi, mictilis, nirvanum, and rufulum. All these deserticolous forms belong to the 
salomonis-group except for alamarum (setuliferum-group), and mictilis and katir (monomorium-group) . 
There is little doubt that intensive collecting in other parts of the continent will yield similar increases in the 
number of known species, and I suspect that the Afrotropical fauna of this large and interesting genus is still 
only fractionally known. 

Key to Afrotropical species-groups (workers) 

1 Mandible with 5 teeth. PF 3,3 (Figs 99, 100) /afiiiode-group(p. 429) 

— Mandible with 3-4 teeth. PF 2,2 or 1,2 2 

2 Mandibles sculptured , longitudinally striate to rugose or uniformly granular 3 

— Mandibles unsculptured except for hair-pits, smooth and shining 6 

3 Propodeal spiracle an ellipse or short slit, its orientation vertical or nearly so (Fig. 33). 

Antennal club not strongly differentiated (Fig. 31). Polymorphic species with strongly 
bidentate anterior clypeal margin (Figs 31 , 32) scabriceps-group (p. 320) 

— Propodeal spiracle circular to subcircular. Antennal club strongly defined. Monomorphic or 

polymorphic species but if the latter then anterior clypeal margin lacking teeth 4 

4 Propodeal dorsum transversely striate to costulate, even if only faintly so 

destructor-group (part; p. 322) 

— Propodeal dorsum smooth or variously sculptured but never transversely striate or costulate .... 5 

5 Eyes situated in front of midlength of sides. In profile the eyes reniform or drawn out 

anteroventrally into a lobe or point (Figs 57-59). Mandibles with 3 or 4 teeth, if 4 then the 
basalmost is reduced to a minute offset denticle setuliferum-group (part; p. 365) 

— Eyes situated at or very close to the midlength of the sides (Figs 42-44, 51-53). In profile the 

eyes not reniform nor drawn out anteroventrally into a lobe or point (Figs 36-38, 45-47, 50, 
55, 56). Mandibles with 4 teeth, only extremely rarely the basalmost tooth reduced 

salomonis-group (part; p. 329) 

6 Eyes minute, reduced to a single ommatidium or with 2 ommatidia at most (Figs 93, 94) 

/bssu/afum-group (p. 420) 

— Eyes larger, distinctly with more than 2 ommatidia 7 

7 Frontal lobes closely approximated, the strip of clypeus running between them narrower or 

only fractionally wider than either of the frontal lobes. Propodeum angular to bidentate in 
profile (Figs 97, 98) banneW-group (p. 425) 

— Frontal lobes farther apart, the strip of clypeus running between them broader, usually 

conspicuously broader, than either of the frontal lobes . Propodeum rounded 8 

8 Propodeal dorsum transversely striate or costulate , even if only faintly so 

destructor-group (part; p. 322) 

— Propodeal dorsum smooth, reticulate-punctate or sometimes otherwise sculptured, never 

transversely striate or costulate 9 

9 Eyes reniform in profile (Fig. 57) setuliferum-group (part; p. 365) 

— Eyes not reniform in profile 10 

10 Antennae with 12 segments. Dorsal alitrunk without standing hairs of any description 

sa/omonis-group (part; p. 329) 

— Antennae with 11 or 12 segments. If the latter then dorsal alitrunk with standing hairs present 

at least at the pronotal humeri monomorium-group (p. 371) 



Synonymic list of Afrotropical species 



scabriceps-group 

abyssinicum (Forel) 
desfrucfor-group 
destructor (Jerdon) 
ominosa Gerstacker 
atomaria Gerstacker 
basalis Smith 
gracillima Smith syn. n. 
vexator Smith 



SOLEHOPSIS GENUS-GROUP 303 



emery/ M ay r 
epinotale Santschi 
mayri Forel stat. n. 

destructor r. gracillimum var. karawajewi Forel (unavailable) 
oscaris Forel 

dispar Emery syn. n. 

solleri Forel syn. n. 

destructor subsp. kalahariense Forel syn. n. 

destructor subsp. kalahariense var. despecta Forel (unavailable) 

amblyops r. bulawayense Forel (homonym) 

amblyops r. prossae Forel (replacement name) syn. n. 
robustior Forel stat. n. 
sa/omo/us-group 
at rum Andre 

afrum var. asmarensis Forel syn. n. 

afrum var. fultor Forel syn. n. 
albopilosum Emery 

albopilosum var. r/ia/es Forel syn. n. 

albopilosum st. paucipilosa Santschi syn. n. 

albopilosum var. clarithorax Santschi syn. n. 

albopilosum subsp. /zngo Arnold syn. n. 
anceps Emery stat. n. 
areniphilum Santschi 

salomonis var. pullula Santschi syn. n. (provisional) 

salomonis var. lepineyi Santschi syn. n. (provisional) 
australe Emery 

subopacum r. australe var. laeviceps Emery (unavailable) 
bicolor Emery 

bicolor var. coerulescens Santschi 

bicolor var. rufibasis Santschi syn. n. 

bicolor var. rufobasalis Santschi (misspelling) 

bicolor var. uelense Santschi syn. n. 

bicolor var. uluense Santschi (misspelling) 

bicolor var. aequatoriale Santschi syn. n. 

bicolor var. tropicale Santschi syn. n. 
carbo Forel stat. n. 
dakarense Santschi stat. n. 
damarense Forel stat. n. 

salomonis var. unicolor Stitz syn. n. 
delagoense Forel 

salomonis r. delagoense var. grahamstownensis Forel (unavailable) 

delagoense var. lacrymans Arnold syn. n. 
dictator Santschi stat. n. 

bicolor st. personatum var. impuriceps Santschi (unavailable) 
disertum Forel stat. n. 

termitarium st. disertum var. petulans Santschi (unavailable) 
drapenum sp. n. 
esharre sp. n. 
excelsior Arnold stat. n. 

speculiceps Santschi syn. n. 
fridae Forel stat. n. 
herero Forel stat. n. 
hirsutum Forel stat. n. 
i/gj'j Forel 
junodi Forel stat. n. 

delagoense var. pretoriensis Arnold syn. n. 
kitectum sp. n. 
mantazenum sp. n. 
marshi sp. n. 



304 B. BOLTON 

mediocre Santschi 
micropacum sp. n. 
minor Stitz stat. n. 
nirvanum sp. n. 
ocellatum Arnold 
opacior sp. n. 

salomonis r. junodi var. opacior Forel (unavailable) 

delagoense st. junodi var. serenum Santschi (unavailable) 
opacum Forel 
ophthalmicum Forel 
orangiae Arnold 
osiridis Santschi 
parvinode Forel stat. n. 
personatum Santschi stat. n. 

bicolor st. personatum var. bimaculatum Santschi (unavailable) 

bicolor st. personatum var. bimaculatoides Ettershank (unnecessary replacement name) 
p/iaraoii/s(L.) 

antiguensis F. 

domestica Shuckard 

minuta Jerdon 

vastator Smith 

fragilis Smith 

contigua Smith 
rabirium sp. n. 
rufulum Stitz stat. n. 

monardi Santschi syn. n. 
senegalense Roger (nomen dubium) 
subdentatum Forel 
subopacum (Smith) 

glyciphila Smith syn. n. 

mediterraneum Mayr 

salomonis st. subopacum var. senegalensis Santschi (unavailable) 

surcoufi Santschi syn. n. 

cabrerai Santschi syn. n. 

salomonis st. subopacum var. liberta Santschi (unavailable) 

cabrerae [sic] st. obscuripes Santschi 

salomonis subsp. subopaca var. claveaui Emery (unnecessary replacement name) 

salomonis subsp. subopacum var. santschiellum Wheeler (unnecessary replacement name) 

subopacum subsp. italica Baroni Urbani 
sutu sp. n. 
tchetichofi Forel 
termitarium Forel stat. n. 
vatranum sp. n. 
viator Santschi 
westisp. n. 
willowmorense sp. n. 

salomonis r. herrero [sic] var. willowmorensis Forel (unavailable) 

salomonis r. herrero [sic] var. fee/// Forel (unavailable) 
zu/u Santschi 
sefu/iferum-group 
alamarum sp. n. 
ebangaense Santschi stat. n. 

nyasae Arnold syn. n. 
hannonis Santschi 
havilandi Forel 

distinctum Arnold syn. n. 

distinctum var. leviceps Arnold syn. n. 
macrops Arnold stat. n. 
notulum Forel stat. n. 






SOLENOPSIS GENUS-GROUP 305 



setuliferum var. dolichops Santschi syn. n. 

setuliferum var. latior Santschi syn. n. 
setuliferum Forel 
xanthognathum Arnold 
monomorium-group 
affabile Santschi 

africanum Forel (nomen nudum) 
altinode Santschi 

altinode var. bondroiti Santschi syn. n. 
angustinode Forel 
arboreum Weber stat. n. 
arnoldi Forel 
balathir sp. n. 
bequaerti Forel 
bevisi Arnold 
binatu sp. n. 
boerorum Forel stat. n. 
borlei Santschi stat. n. 
braunsi Mayr 
captator Santschi 
crawleyi Santschi 
disoriente sp. n. 
dolatu sp. n. 
draxocum sp. n. 
egens Forel 

jucundum Santschi syn. n. 

longiusculum Santschi syn. n. 
excensurae Forel stat. n. 
exchao Santschi 
exiguum Forel 

exiguum var. bulawayensis Forel syn. n. 

faurei Santschi syn. n. (provisional) 

exiguum x.flavescens Forel syn. n. (provisional) 
fasciatum Santschi (nomen dubium) 
fastidium sp. n. 
firmum Santschi 
tloricola (Jerdon) 

poecilum Roger 

cinnabari Roger 

specularis Mayr 

impressum Smith syn. n. 

angusticlava Donisthorpe syn. n. 
fugelanum sp. n. 
gabrielense Forel stat. n. 
guillarmodi Arnold 
holothirsp. n. 
inquietum Santschi 
iyenasu sp. n. 
katir sp. n. 
kelapre sp. n. 
/tinefi Weber stat. n. 
/ene Santschi 
leopoldinum Forel stat. n. 

explorator Santschi syn. n. 

aequum Santschi syn. n. 

estherae Weber syn. n. 
lubricum Arnold 
malatu nom. n. 

altinode Santschi (homonym) 



306 B. BOLTON 

manirsp. n. 
ma vide sp. n. 
mictilis Forel stat. n. 

exiguum st. mictile var. sudanicum Santschi (unavailable) 

minutissimum Santschi syn. n. (provisional) 
mirandum Arnold 
musicum Forel 
noxitum sp. n. 
nuptualis Forel stat. n. 
occidentale Bernard 
pads Forel (nomen dubium) 
pallidipes Forel stat. n. 
paternum sp. n. 

oscaris r. springvalense var. paterna Forel (unavailable) 
pulchrum Santschi 
rastractum sp. n. 
rhopalocerum Emery 

minutum subsp. hottentota Emery syn. n. (provisional) 

leimbachi Forel syn. n. 
rosae Santschi 

cotterelli Donisthorpe syn. n. 
rotundatum Santschi 
schultzei Forel 
shilohense Forel stat. n. 
spectrum sp. n. 
speluncarum Santschi stat. n. 
springvalense Forel 
sryetum sp. n. 
strangulation Santschi 
symmotu sp. n. 
tablense Santschi stat. n. 
taedium sp. n. 
tanysum sp. n. 
forvi'ctesp. n. 
fra/te sp. n. 
tynsorum sp. n. 
vaguum Santschi 
vecfesp. n. 
vonatu sp. n. 
fossu/afum-group 

cryptobium (Santschi) comb. n. 
elgonense (Santschi) comb. n. 
jonesi Arnold 

arnoldi Santschi (homonym) 
malamixtum sp. n. 
modestum Santschi 

modestum var. boerorum Santschi (homonym) 

modestum var. transwaalensis Emery (first replacement name) syn. n. 

modestum var. smutsi Wheeler (second replacement name) syn. n. 
sersalatum sp. n. 
thrascoleptum sp. n. 
Aaime/i-group 
guineense (Bernard) 
hanneli Forel 

moestum Santschi syn. n. 
invidium sp. n. 
jacksoni sp. n. 
valtinum sp. n. 
/af/node-group 



SOLENOPSIS GENUS-GROUP 307 

latinode Mayr 

latinode var. bruneum Emery syn. n. 
voeltzkowi Forel syn. n. 

Key to Afrotropical species (workers) 

Notes. The nomina dubia fasciatum, pads, and senegalense are omitted from the key. Density and 
distribution of pilosity are important at several points in the key; old or abraded specimens must be treated 
with caution. 

1 Antennae with 12 segments 2 

— Antennae with 1 1 segments 145 

2 Mandibles sculptured; either longitudinally rugose, or striate-rugulose, or costulate, or having 

a granular mat with superimposed fine striae over most or all of the mandible; the sculpture 
usually very conspicuous, the mandibles never smooth 3 

— Mandibles unsculptured; either entirely smooth and highly polished, or smooth with scattered 

hair-pits, or at most with 1-2 minute striae at the extreme base; mandibles never with 
extensive conspicuous sculpture as described above 66 

3 With the head in full-face view the cephalic dorsum from the level of the midlength of the eyes 

to the occipital margin with surface sculpture present other than small separated hair-pits. 
The sculpture may be striate, reticulate-punctate, shagreened, granular, or a combination of 
these; or the surface may have only feeble to vestigial superficial reticular patterning, but the 
surface is never entirely smooth and featureless except for hair-pits 4 

— With the head in full-face view the cephalic dorsum from the level of the midlength of the eyes 

to the occipital margin without surface sculpture present, the entire surface smooth and 
featureless except for scattered hair-pits; very rarely a few fine transverse rugulae may occur 
at the occipital margin itself 59 

4 Promesonotal dorsum with standing hairs present, at least a single pair at the pronotal humeri 5 

— Promesonotal dorsum without standing hairs of any description 17 

5 Propodeal dorsum with numerous standing hairs, obviously more than a single pair 6 

— Propodeal dorsum without standing hairs or sometimes with a single pair at most 10 

6 Basal (fourth) tooth of mandible only slightly smaller than third tooth. Scapes longer and head 

relatively long and narrow, SI 99-121 , CI 73-83 7 

— Basal (fourth) tooth of mandible reduced to a minute denticle which is only a fraction the size of 

the third tooth. Scapes shorter and head relatively short and broad, SI 63-88, CI 85-95 8 

7 Head, alitrunk, petiole, postpetiole and appendages bright orange to orange-yellow, the gaster 

dark brown to blackish, the two colours strongly contrasting. CI 81-83, SI 99-103; maximum 
diameter of eye 0-19-0-21 x HW. (Ethiopia) hirsutum(p. 345) 

— Entire body more or less uniformly coloured brown to blackish, sometimes gaster darker in 

shade but without strongly contrasting areas of colour as above. CI 73-78, SI 110-120; 
maximum diameter of eye 0-22-0-25 x HW (Figs 38, 44). (Malawi, Zimbabwe, South 
Africa) albopilosum(p. 335) 

8 Dorsum of head and alitrunk entirely reticulate-punctate, without trace of striate or rugulose 

sculpture. First gastral tergite reticulate-punctate on basal one-third to one-half. Eyes 
weakly reniform in profile, their anterior margins drawn out into anteroventrally directed 
points. (Congo) hannonis(p. 368) 

— Dorsum of head, alitrunk or both with striate or rugulose sculpture present at least in part, or 

partially smooth; not evenly reticulate-punctate everywhere. First gastral tergite smooth 
basally except for hair-pits. Eyes oval in profile 9 

9 Dorsal surfaces of head and alitrunk all evenly coarsely sculptured, the propodeum not more 

strongly sculptured than the head and promesonotum. Body colour light brown to blackish 
brown. (Malawi, Botswana, Zimbabwe , Mozambique , South Africa) emeryi(p. 325) 

— Dorsal surfaces of head and alitrunk not evenly coarsely sculptured, the propodeum more 

strongly sculptured than the head and promesonotum, the latter usually with extensive 
smooth areas; cephalic sculpture very faint. Body colour yellow. (Ghana, Nigeria, Ethiopia, 

Uganda, Zaire, Tanzania, Zimbabwe, Botswana, South Africa) oscaris (part; p. 326) 

10 Sculpture of promesonotal dorsum virtually effaced, leaving the surface smooth and with faint 

to vestigial superficial reticular patterning only 11 

— Sculpture of promesonotal dorsum consisting of dense reticulate-punctation or of strong and 

conspicuous reticulation, the sculpture always distinct 12 



308 B. BOLTON 

11 Yellow species with HW<0-65, SI 102-105; eyes with maximum diameter 0-33 x HW. 

(Ethiopia) HgH(P- 346) 

— Glossy dark brown species with HW>0-75, SI 114-122; eyes with maximum diameter 

0-22-0-25 x HW. (South Africa) excelsior(p. 344) 

12 Dorsum of head from level of midlength of eyes to occipital margin uniformly densely 

blanketed with sharply defined reticulate-punctate sculpture 13 

— Dorsum of head from level of midlength of eyes to occipital margin not uniformly blanketed 

with sharply defined reticulate-punctate sculpture; either the surface finely shagreened with 
a few punctulate patches, or only with fine shagreening, reticulation, or with superficial 
reticular patterning only 15 

13 Ventral surface of head with numerous extremely long anteriorly curved J-shaped ammochaete 

hairs (Fig. 36). Scapes relatively long, SI 117-128. (Angola, Namibia, Botswana, 
Zimbabwe) rufulum (part; p. 359) 

— Ventral surface of head with a few short hairs which may be straight or curved, but lacking long 

J-shaped ammochaete hairs. Scapes relatively short, SI 85-1 15 14 

14 Small species, HW 0-40-0-48; SI 104-115 (Figs 56, 60). Eyes with 7 or fewer (usually 6) 

ommatidia in the longest row. Head and alitrunk yellow to very light yellow-brown. 
(Cosmopolitan tramp-species, frequent in houses and other buildings) pharaonislp. 356) 

— Larger species, HW 0-57-0-80; SI 85-100. Eyes with 9-11 ommatidia in the longest row. Head 

and alitrunk dark brown to blackish. (Zimbabwe, Botswana, South Africa) junodi(p. 346) 

15 Eyes with maximum diameter 0-22-0-24 x HW; scapes short and head broad, SI 88-95, CI 

80-85. Projecting median portion of clypeus with its anterior free margin conspicuously 
concave. (South Africa) delagoense(p. 341) 

— Eyes with maximum diameter 0-27-0-31 x HW; scapes long and head narrow, SI 113-130, CI 

70-76. Projecting median portion of clypeus with its anterior free margin transverse to 
convex 16 

16 Pronotum with a single pair of standing hairs, situated at the humeri (Fig. 55). SI 113-120. 

Alitrunk dark brown to blackish, approximately the same colour as the gaster. (Namibia) 

vatranum(p. 362) 

— Pronotum with 2-3 pairs of standing hairs on the dorsum behind the pair situated at the humeri 

(Fig. 50). SI 124-130. Alitrunk light to dull orange, the gaster dark brown to black and 
distinctly much darker than the alitrunk. (Namibia) marshi(p. 349) 

17 First gastral tergite with appressed pubescence but lacking standing (erect to subdecumbent) 

longer hairs anterior to the transverse row at the apex of the sclerite; sometimes even the 
apical transverse row of hairs absent 18 

— First gastral tergite with appressed pubescence and always with standing (erect to subdecum- 

bent) longer hairs also present anterior to the transverse row at the apex of the sclerite. 
Standing hairs on the first gastral tergite varying from numerous to a single pair situated at 
one-third or one-half of the length of the sclerite 28 

18 Dorsum of head uniformly blanketed with granular or shagreenate sculpture, or uniformly 

reticulate-punctate , the surface opaque 19 

— Dorsum of head only with very faint superficial reticular patterning which appears inlaid 

into the surface, without raised or roughened sculpture, the surface polished smooth and 
shining 24 

19 With the head in profile the eyes drawn out anteroventrally into a point or lobe , the long axis of 

the eye directed obliquely downwards from back to front and very obviously out of alignment 
with the long axis of the head (Fig. 57) . Eyes situated in front of the midlength of the sides of 
the head. Fourth (basal) tooth of mandible much smaller than the third and frequently 
reduced to an offset small denticle. Scapes shorter, SI 80-90 20 

— With the head in profile the eyes normal, not drawn out anteroventrally into a point or lobe, the 

long axis of the eye about parallel to the long axis of the head (Figs 45 , 46) .Eyes situated at or 
very near to the midlength of the sides of the head. Fourth (basal) tooth of mandible as large 
as or only slightly smaller than the third . Scapes longer, SI 98-1 16 22 

20 Eyes relatively large, maximum diameter 0-29-0-33 x HW, conspicuously reniform in profile 

and with the ventral ocular margin concave (Fig. 57) . (Botswana) setuliferum (p. 370) 

— Eyes smaller, maximum diameter 0-23-0-28 x HW, drawn out into a lobe or point antero- 

ventrally but not reniform, the ventral ocular margin shallowly convex to flat or rarely 
extremely feebly concave 21 

21 Sculpture on dorsum of pronotum entirely of sharply defined reticulate-punctation. Posterior 






SOLENOPSIS GENUS-GROUP 309 

one-third of cephalic dorsum reticulate-punctate. (Angola, Malawi) ebangaense(p. 367) 

— Sculpture on dorsum of pronotum of partially effaced or shagreenate reticulate-punctation , the 

punctures not sharply defined everywhere and frequently only with a shagreenate appear- 
ance. Posterior one-third of cephalic dorsum silky or even striolate, the sculpture with a 
smeared amorphous appearance, not sharply reticulate-punctate. (Angola, Zimbabwe, 
South Africa) notulum (p . 370) 

22 With the head in profile the posteroventral occipital angles not broadly evenly convex; instead 

the angles are either bluntly right-angled or acute (Fig. 45). Viewed from above and behind 
the posteroventral occipital angles prominent and acute. Dorsum of head from level of 
midlength of eyes to occipital margin usually uniformly sharply reticulate-punctate. 
Maximum diameter of eyes 0-24-0-27 x HW. Larger species, HW 0-66-0-80. (Ethiopia, 
Sudan, Kenya, Rwanda, Tanzania, Zaire, Central African Republic, Zimbabwe, Ivory 
Coast, Ghana) afrum (p. 334) 

— With the head in profile the posteroventral occipital angles evenly broadly rounded (Fig. 46). 

Viewed from above and behind the posteroventral occipital angles broadly rounded, not 
prominent. Dorsum of head from level of midlength of eyes to occipital margin usually not 
uniformly reticulate-punctate but instead granulate to shagreenate, with a silky appearance 
or with extremely fine striolae. Either eyes large, maximum diameter 0-30-0-35 x HW(with 
HW range 0-67-0-88), or much smaller species with HW 0-42-0-51 23 

23 Eyes with 12-14 ommatidia in the longest row. Larger species with broader head and shorter 

scapes, HW 0-67-0-88, CI 78-88, SI 98-104. With alitrunk in profile the promesonotal 
outline with the posterior portion of the mesonotum sharply downcurved and descending to 
the impressed metanotal groove (Fig. 46). (Sudan, Mali, Niger, Senegal) 

areniphilum (part; p. 336) 

— Eyes with 7-9 ommatidia in the longest row. Smaller species with narrower head and longer 

scapes, HW 0-42-0-51, CI 72-75, SI 110-116. With alitrunk in profile the promesonotal 
outline approximately flat to the metanotal groove. (Namibia, Botswana) 

damarense (part; p. 340) 

24 With the head in full-face view the eyes situated conspicuously in front of the midlength of the 

sides 25 

— With the head in full-face view the eyes situated at or very close to the midlength of the 

sides 26 

25 Dark brown larger species, HW 0-56-0-68. Eyes larger, maximum diameter 0-33-0-36 x HW. 

In profile the eyes drawn out into an anteroventrally directed lobe, the eyes weakly reniform 
in shape (Fig. 58). Head somewhat broader and scapes shorter, CI 79-83, SI 80-90. 
(Namibia) alamarum(p. 367) 

— Yellow smaller species, HW 0-33-0-36. Eyes smaller, maximum diameter 0-26-0-28 x H W. In 

profile the eyes approximately oval. Head somewhat narrower and scapes longer, CI 75-77, 

SI 92-97. (Botswana) rabirium (part; p. 358) 

26 Node of petiole with a single pair of hairs, which project posteriorly. Scapes slightly longer and 

eyes larger, SI 95-100, maximum diameter of eyes 0-26-0-28 x HW. (Namibia) 

nirvanum (p. J351) 

— Node of petiole without projecting hairs. Scapes slightly shorter and eyes smaller, SI 90-95, 

maximum diameter of eyes 0-21-0-25 x HW 27 

27 Yellow species with relatively broad head, CI 80-84. Eyes exactly at midlength of sides of head 

and their maximum diameter 0-21-0-24 x HW. (Zimbabwe, South Africa) mediocre(p. 349) 

— Blackish brown species with relatively narrow head, CI 77-78. Eyes slightly in front of 

midlength of sides of head and their maximum diameter 0-24-0-25 x HW. (Namibia) 

esharre(p. 343) 

28 Eyes extremely large, maximum diameter 0-37-0-40 x HW, and scapes with SI > 110 (Fig. 

52) . (Namibia) viator (p. 363) 

— Either eyes smaller, maximum diameter <0-36 x HW, or scapes shorter, SI < 110, or both 29 

29 Dorsum of head from level of midlength of eyes to occipital margin with extremely faint 

vestigial superficial reticular patterning only, the surface polished and shining 30 

— Dorsum of head from level of midlength of eyes to occipital margin with granular or 

shagreenate sculpture, or uniformly reticulate-punctate, the surface opaque and never only 

with superficial reticular patterning 36 

30 Dorsum of head behind level of frontal lobes with appressed pubescence but without standing 

hairs of any description 31 



310 B. BOLTON 

— Dorsum of head behind level of frontal lobes with appressed pubescence and with standing 

hairs also present. The standing hairs are usually sparse and arranged in pairs on each side of 
the midline; generally a conspicuous pair present close to the point where the dorsum curves 
into the occipital margin 33 

31 Eyes relatively large and scapes relatively short; maximum diameter of eye 0-35 x HW and SI 

92. (Ethiopia) ophthalmicum(p. 353) 

— Either eyes relatively small or scapes relatively long, or both; maximum diameter of eye 

<0-35 x HW (range 0-24-0-31 x HW) and SI 88-102, but if SI 88-93 then eyes are only 
0-24-0-26 xHW 32 

32 Alitrunk in profile with promesonotal dorsal outline evenly convex from front to back, highest 

at about the midlength. Propodeal dorsal outline forming a separate surface behind the 
conspicuous metanotal groove, not merely continuing the slope of the promesonotal dorsum 
(Fig. 54). HW 0-50-0-60, CI 79-93, SI 88-93; maximum diameter of eye 0-24-0-26 x HW. 
(South Africa) wiIlowmorense(p. 364) 

— Alitrunk in profile with promesonotal dorsal outline almost flat and sloping from front to back, 

its highest point well in front of the midlength. Propodeal dorsal outline continuing the slope 
of the promesonotum behind the virtually unimpressed metanotal groove (Fig. 49). HW 
0-43-0-45, CI 73-75, SI 100-102; maximum diameter of eye 0-29-0-31 x HW. (Namibia) 

kitectum(p. 347) 

33 Small species with relatively large eyes, HW 0-46-0-52, maximum diameter of eye 0-28-0-32 x 

HW. CI 73-78. Peduncle of petiole anteroventrally with a conspicuous lamellate blunt tooth 

or prominent lobe (Fig. 48) . (Namibia) drapenum(p. 342) 

— Larger species with relatively small eyes, HW 0-67-0-80, maximum diameter of eye 0-21-0-23 

x HW. CI 80-86. Peduncle of petiole anteroventrally with an angle which is usually broadly 

and bluntly rounded, without a lamellate tooth or prominent lobe 34 

34 Sculpture of promesonotal dorsum almost effaced. Node of postpetiole dorsally unsculptured, 

smooth and shining. With propodeum in dorsal view the posteriorly divergent ridges 
separating the dorsum from the sides sharply defined and narrowly rounded. (South Africa) 

orangiae(p. 354) 

— Sculpture of promesonotal dorsum fine but conspicuous. Node of postpetiole dorsally with fine 

granular to punctulate sculpture. With propodeum in dorsal view the posteriorly divergent 
ridges separating the dorsum from the sides very poorly defined and broadly rounded, often 
virtually effaced 35 

35 Slightly larger species with fractionally broader head and shorter scapes, HW 0-74-0-82, CI 

82-86, SI 95-100. (South Africa) tchelichoG (p. 362) 

— Slightly smaller species with fractionally narrower head and longer scapes, HW 0-67-0-68, CI 

80-81, SI 101-103. (South Africa) fridae (p. 344) 

36 With the head in full-face view the cephalic dorsum from the level of the posterior margins of 

the eyes to the occipital margin uniformly densely reticulate-punctate; each puncture sharply 
defined and either of approximately equal size over the entire surface or becoming smaller 
posteriorly; without trace of any other form of sculpture 37 

— With the head in full-face view the cephalic dorsum from the level of the posterior margins of 

the eyes to the occipital margin not uniformly reticulate-punctate. Instead the surface is 
more or less opaque, with shagreenate to punctate-shagreenate or extremely fine striolate 
sculpture, or with a silky, smeared or roughened appearance; but not having sharply defined 
reticulate-punctation everywhere 44 

37 Head and alitrunk uniformly brown to black, the gaster approximately the same colour or 

slightly darker, not strongly contrasting with the head and alitrunk 38 

— Head and alitrunk red to bright orange-yellow, frequently orange-red, the gaster much darker 

and strongly contrasting with the head and alitrunk 40 

38 First gastral tergite with about 10 pairs of hairs in front of the apical transverse row. Smaller 

species, HW0-48,SL0-50-0-51,PW0-33-0-34. (South Africa) micropacum (p. 350) 

— First gastral tergite with only 1-2 pairs of hairs in front of the apical transverse row. Larger 

species, HW > 0-60, SL > 0-60, PW > 0-40 39 

39 In profile the propodeal dorsum sloping posteriorly, the junction of dorsum and declivity 

indicated by a sharply defined or subdentate angle. (Zaire) subdentatum(p. 359) 

— In profile the propodeal dorsum about horizontal, the dorsum rounding evenly into the 

declivity without passing through a sharp or subdentate angle. (Uganda, Zaire, Angola, 
Zambia, Zimbabwe) opacum (p. 353) 



SOLENOPSIS GENUS-GROUP 311 

40 Basal (fourth) tooth of mandible reduced to a minute denticle, only a fraction the size of the 

third tooth. Ventral surface of head with numerous extremely long anteriorly curved 
J-shaped ammochaete hairs (Fig. 36). (Angola, Namibia, Botswana, Zimbabwe) 

rufulum (part; p. 359) 

— Basal (fourth) tooth of mandible either about the same size as the third tooth or only slightly 

smaller, not reduced to a minute denticle. Ventral surface of head with simple hairs which 

may be straight or curved , but lacking extremely long J-shaped hairs 41 

41 Eyes relatively large, maximum diameter 0-31-0-33 x HW. (Angola) personatum (p. 356) 

— Eyes relatively small , maximum diameter 0-23-0-27 x HW 42 

42 Pilosity on basal half of first gastral tergite sparse, usually with only 1-3 pairs of hairs. Very 

rarely 4 pairs may occur, in which case the anterior free margin of the median portion of 
the clypeus is shallowly impressed, the projecting angles on each side of the impression 
low broad and blunt. (Ethiopia, Sudan, Djibouti, Kenya, Liberia, Burkina Faso, 
Ghana, Nigeria, Togo, Cameroun, Zaire; also occurring in North Africa and the Arabian 
Peninsula) bicolor(p. 338) 

— Pilosity on basal half of first gastral tergite dense, usually with 6-8 pairs of hairs. If pilosity at 

lower end of this range then the anterior free margin of the median portion of the clypeus is 
deeply indented and the projecting angles on each side of the indentation form sharp 
prominent teeth 43 

43 Anterior free margin of median portion of clypeus concave in full-face view, the concavity 

flanked by a pair of freely projecting acute teeth (Fig. 43). (Kenya) westi(p. 363) 

— Anterior free margin of median portion of clypeus shallowly concave in full-face view and 

flanked by a pair of bluntly rounded angles, without projecting teeth. (Angola) . . . dictator(p. 341) 

44 Standing hairs on first gastral tergite, discounting the apical transverse row, numerous and 

more or less evenly distributed; obviously with more than 3 pairs present and the hairs not 
restricted to the basal half of the sclerite 45 

— Standing hairs on first gastral tergite, discounting the apical transverse row, sparse and 

restricted in distribution; with only 1-3 pairs present which are generally confined to the 
basal half of the sclerite . When only one pair present it is usually at the midlength 50 

45 Alitrunk and gaster approximately the same colour, the two not strongly contrasting 46 

— Alitrunk and gaster conspicuously differently coloured , the two obviously strongly contrasting 48 

46 Dimensions in range HW 0-53-0-60, SL 0-62-0-72, CI 74-77, SI 117-122. (Namibia) 

mantazenum(p. 348) 

— Dimensions in range HW 0-43-0-51, SL 0-44-0-58, CI 70-74, SI 102-1 16 47 

47 Uniformly yellow species. SI 108-116. Maximum diameter of eye 0-26-0-30 x HW. (Angola, 

Namibia) minor(p. 350) 

— Uniformly brown species. SI 102-107. Maximum diameter of eyeO. 24-0. 26 x HW. 

(Ethiopia) carbo(p. 339) 

48 Larger species, HW 0-59-0-69, SL 0-60-0-70, PW 0-43-0-48, length of hind femur 0-70-0-82, 

maximum diameter of eye 0-16-0-17. Propodeal dorsum shallowly but distinctly transversely 
concave. In available material larger workers with a single ocellus present. (South Africa) 

ocellatum(p. 352) 

— Smaller species, HW 0-44-0-47, SL 0-44-0-45, PW 0-30-0-31, length of hind femur 0-48-0-50, 

maximum diameter of eye 0-10-0-14. Propodeal dorsum not concave. No ocelli developed ... 49 

49 Head and alitrunk orange-yellow, gaster blackish brown. Maximum diameter of eye 0-23-0-24 

x HW, with 7-8 ommatidia in the longest row. (Senegal) dakarense(p. 339) 

— Head and alitrunk medium yellowish brown, gaster dark brown. Maximum diameter of eye 

0-30 x HW, with 10 ommatidia in the longest row. (Ethiopia, Sudan) parvinode(p. 355) 

50 Eye with 10 or more ommatidia in the longest row. HW 0-50-0-88 51 

— Eye with 7-9 ommatidia in the longest row. HW 0-43-0-52 54 

51 Dorsal outline of alitrunk in profile very characteristically shaped (Fig. 46), the posterior 

one-third or more of the mesonotum suddenly downcurved and descending steeply to the 
metanotal groove. Larger species, HW 0-67-0-88. (Sudan, Mali, Niger, Senegal; also 
present north of the Sahara Desert) areniphilum (part; p. 336) 

— Dorsal outline of alitrunk in profile not shaped as above, the posterior one-third of the 

mesonotum continuing the even gradually curved slope of the anterior portion , not suddenly 
downcurved and steeply descending. Smaller species, HW 0-50-0-64 52 

52 Smaller species with relatively very large eyes, HW 0-50-0-57, maximum diameter of eye 

0-35-0-38 x HW. (Kenya) suto(p. 361) 



312 B. BOLTON 

— Larger species with relatively small eyes , HW ■ 54-0 • 64 , maximum diameter of eye • 24-0 • 30 

xHW 53 

53 Prominent median section of clypeus with its anterior free margin indented centrally. Dorsum 

of head with 0-1 pairs of standing hairs behind the level of the frontal lobes. Maximum 
diameter of eye 0-27-0-30 x HW. Promesonotum reticulate-punctate dorsally. Cephalic 
sculpture strong, granulate to shagreenate-punctate. (Senegal, Niger; widespread north of 
the Sahara, in European lands bordering the Mediterranean, and Middle East to India; 
present as an introduction in South Africa , Madagascar and Sri Lanka) subopacum (p . 360) 

— Prominent median section of clypeus with its anterior free margin transverse. Dorsum of head 

with 3-4 pairs of standing hairs behind the level of the frontal lobes. Maximum diameter of 
eye 0-24-0-26 x HW. Promesonotum with weak reticular patterning dorsally. Cephalic 
sculpture feeble, superficially reticulate without overlying granulate or shagreenate- 
punctate component. (Namibia: Possession I.) herero(p. 345) 

54 Antennal scapes both absolutely and relatively shorter, SL 0-40-0-43, SI 89-93. (Zimbabwe) 

disertum(p. 342) 

— Antennal scapes both absolutely and relatively longer, SL 0-47-0-57, SI 100-110 55 

55 Shagreenate-granular sculpture of dorsal head and pronotum strongly developed, the surfaces 

everywhere dull and opaque 56 

— Shagreenate-granular sculpture of dorsal head and pronotum very feebly developed, the 

surfaces semi-smooth and weakly shining 57 

56 Dorsum of head with 2 pairs of standing hairs behind level of frontal lobes. Eyes averaging 

somewhat smaller, 0-24-0-26 x HW. (Botswana, Zimbabwe, South Africa) opacior(p. 352) 

— Dorsum of head without standing hairs behind level of frontal lobes. Eyes averaging somewhat 

larger, 0-27-0-31 x HW. (Namibia, Botswana) damarense (part; p. 340) 

57 Entirely yellow. (Botswana) termitarium (p. 362) 

— Head and alitrunk medium brown, gaster dark brown 58 

58 Dorsum of pronotum finely shagreenate, with a roughened silky appearance; dorsum of 

mesonotum reticulate-punctate, the two forms of sculpture contrasting. Slightly smaller 
species, HW 0-47, SL 0-47. (South Africa) anceps (p. 336) 

— Dorsum of pronotum finely reticulate, dorsum of mesonotum reticulate-punctate; the two not 

contrasting but rather the sculpture of the former appearing as a reduced version of that of 

the latter. Slightly larger species, HW 0-50-0-52, SL 0-50-0-54. (South Africa) . . . australe(p. 337) 

59 Propodeal spiracle vertically slit-shaped or elliptical. Anterior clypeal margin with a pair of 

prominent strong teeth which overhang the mandibles (Figs 31, 32), these teeth widely 
separated and the distance between them greater than the maximum width across the frontal 
lobes. (Ethiopia, Sudan, Burkina Faso, Nigeria, Benin, Ghana) abyssinicum(p. 321) 

— Propodeal spiracle circular to subcircular. Anterior clypeal margin lacking prominent teeth of 

any description 60 

60 Propodeal dorsum reticulate-punctate. Eyes relatively large, maximum diameter 0-27-0-33 x 

HW 61 

— Propodeal dorsum finely transversely striolate to transversely rugulose, sometimes the sculp- 

ture very reduced in small workers so that the surface appears virtually smooth. Eyes 
relatively small, maximum diameter 0- 13-0-20 x HW 62 

61 Mesonotum and propodeum dorsally with standing hairs present. Mandibles with only 3 teeth. 

Larger species with relatively broad head and short scapes, HW 0-62-0-69, CI 86-90, SI 
78-82; maximum diameter of eye 0-27-0-30 x HW. (South Africa) ha\ilandi(p 368) 

— Mesonotum and propodeum dorsally without standing hairs or the former with a single short 

pair (Fig. 59). Mandibles with 3 teeth plus a smaller basal denticle. Smaller species with 
relatively narrow head and longer scapes, HW 0-42-0-45, CI 78-80, SI 84-90; maximum 
diameter of eye 0-31-0-33 x HW. (South Africa) macrops(p. 369) 

62 Head yellow, alitrunk dark brown, gaster yellow; the colours of the head and alitrunk strongly 

contrasting. (Zaire) epinotale(p. 326) 

— Head and alitrunk uniformly yellow or uniformly brown, gaster approximately the same colour 

or darker ; the colours of the head and alitrunk not strongly contrasting 63 

63 Head and alitrunk brown, usually dark brown 64 

— Head and alitrunk yellow 65 

64 Species with very little size variation in any given sample, without transverse fine rugular 

sculpture on the posterior surface of the head where it curves down towards the occipital 
foramen (Figs 35, 41). (Somalia, Kenya; also occurs in Madagascar) robustior(p. 328) 



SOLENOPSIS GENUS-GROUP 313 

— Species with marked size variation in any given sample, the medium to large workers with 

transverse fine rugulose sculpture on the posterior surface of the head where it curves down 
towards the occipital foramen (Fig. 34). (Sudan, Mali, Niger; widespread in Africa north of 
the Sahara and in the Near and Middle East) mayri(p. 326) 

65 Petiole node in dorsal view subglobular; postpetiole node in dorsal view only slightly broader 

than long (Fig. 39). (Pantropical tramp, probably of Indian origin) destructor (part; p. 324) 

— Petiole node in dorsal view transverse, distinctly compressed from front to back and obviously 

much broader than long; postpetiole node in dorsal view distinctly broader than long (Fig. 
40). (Nigeria, Ghana, Ethiopia, Uganda, Zaire, Tanzania, Zimbabwe, Botswana, South 
Africa) oscaris (part; p. 326) 

66 Eyes minute and point-like , consisting of only one or two ommatidia (Figs 93, 94) 67 

— Eyes conspicuous, distinctly with more than two ommatidia 74 

67 Metanotal groove in profile a simple indentation of the surface which is scarcely impressed 

(Fig. 95). Propodeum in absolute profile with the dorsum and declivity meeting in a rounded 
or sharp angle, but without small teeth or projecting denticles at their junction. (Ivory Coast, 
Kenya, South Africa) modestum(p. 423) 

— Metanotal groove in profile a sharply impressed U- or V-shaped depression (Fig. 94). 

Propodeum in absolute profile with the dorsum and declivity meeting in a sharp angle which 

is usually equipped with a minute but conspicuous projecting denticle 68 

68 Brown to blackish brown species 69 

— Yellow species 70 

69 Lower half of mesopleuron sculptured . Propodeum in dorsal view with a short transverse crest 

behind the metanotal groove, this crest appearing as a narrow acute peak in profile at the 
summit of the propodeum immediately behind the metanotal groove. (Ivory Coast, Togo) 

malamixtum(p. 423) 

— Lower half of mesopleuron smooth. Propodeum in dorsal view without a transverse crest 

behind the metanotal groove, in profile the propodeal dorsum raised and narrowly rounded 
immediately behind the metanotal groove but this raised portion not surmounted by an acute 
peak. (Ivory Coast, Ghana, Nigeria, Cameroun, Gabon, Zaire) cryptobium (part; p. 421) 

70 Lower half of mesopleuron sculptured . ( Rwanda) sersalatum(p. 424) 

— Lower half of mesopleuron smooth 71 

71 Smaller species, HL 0-36-0-43, HW 0-28-0-34, SL 0-26-0-31. (Ivory Coast, Ghana, Nigeria, 

Cameroun , Gabon , Zaire) cryptobium (part ; p . 42 1 ) 

— Largerspecies,HLO-46-0-55,HWO-38-0-43,SLO-36-0-44 72 

72 Antennal scapes relatively short, SI 91—95. (Kenya) elgonense(p. 422) 

— Antennal scapes relatively long, SI 103-1 10 73 

73 Pubescence of scapes and of sides of head behind eyes dense and erect to suberect (Fig. 93) . CI 

80-83. (Ivory Coast) thrascoleptum (p. 424) 

— Pubescence of scapes and of sides of head behind eyes sparse and short, appressed. CI 72-75. 

(South Africa) jonesi(p. 422) 

74 Dorsum of propodeum sculptured, even if only feebly so, the sculpture consisting of fine 

transverse striation or reticulate-punctation 75 

— Dorsum of propodeum unsculptured, smooth and shining everywhere 88 

75 Dorsal surfaces of alitrunk and first gastral tergite without standing hairs 76 

— Dorsal surfaces of alitrunk or first gastral tergite , or both , with standing hairs present 78 

76 Cephalic dorsum finely shagreenate everywhere except for a smooth median longitudinal 

narrow strip. (Kenya) osiridis(p. 354) 

— Cephalic dorsum smooth or at most sculptured with only the faintest vestiges of superficial 

reticular patterning 77 

77 Pronotal dorsum reticulate to shagreenate. Cephalic dorsum with sculpture close to the 

occipital margin. SI 92-97. (Botswana) rabirium (part; p. 358) 

— Pronotal dorsum unsculptured. Cephalic dorsum smooth with scattered hair-pits close to the 

occipital margin. SI 85-88. (South Africa) zulu(p. 365) 

78 Mandibles with 5 teeth which decrease in size from apex to base. PF3,3. (Tanzania: PembaL; 

widespread in Oriental and Indo-Australian regions) latinode(p. 429) 

— Mandibles with 4 teeth, or 3 teeth plus an offset basal denticle, or with only 3 teeth. PF 2,2 or 

less 79 

79 Central portion of clypeus in full-face view with a pair of strongly anteriorly divergent sharp 

carinae which terminate in a pair of freely projecting teeth or denticles anteromedially. 



314 B. BOLTON 

Frontal lobes closely approximated, the posteriormost portion of the clypeus which runs 
between them redaced to a narrow strip which is only slightly wider than either of the frontal 
lobes (Fig. 97) 80 

— Central portion of clypeus in full-face view without strongly anteriorly divergent sharp carinae 

and lacking freely projecting teeth or denticles anteromedially. Instead the margin here 
is convex to shallowly concave. Frontal lobes farther apart, the posteriormost portion 
of the clypeus which runs between them distinctly much wider than either of the frontal 
lobes 83 

80 Propodeal dorsum strongly transversely rugulose. Mesopleuron, metapleuron and sides of 

propodeum mostly densely sculptured, smooth areas restricted to immediate vicinity of 
propodeal spiracle and a small patch high on the mesopleuron. (Cameroun) jacksoni(p. All) 

— Propodeal dorsum feebly to vestigially transversely striolate. Mesopleuron, metapleuron and 

sides of propodeum mostly to entirely smooth, at most with patches of sculpture over the 
metapleural gland bulla and at the extreme base of the mesopleuron 81 

81 Body colour uniform blackish brown to jet black. (Guinea, Ivory Coast, Ghana, Nigeria, 

Cameroun) invidium (part; p. 427) 

— Body colour light to medium brown 82 

82 Eyes consisting of only 6-7 ommatidia, their maximum diameter 0-13-0- 15 x HW. (Kenya) 

valtinum(p. 428) 

— Eyes consisting of more than 10 ommatidia, their maximum diameter 0-16-0-18 x HW. 

(Kenya) hanneli(p. 426) 

83 Fourth (basal) tooth of mandible only slightly smaller than the third, not reduced to a minute 

offset basal denticle, nor widely separated from the third tooth. Dorsum and sides of 
propodeum blanketed everywhere with dense reticulate-punctate sculpture 84 

— Fourth (basal) tooth of mandible minute, reduced to a tiny offset denticle which is much 

smaller than the third tooth and is widely separated from it. Dorsum and sides of propodeum 
not uniformly reticulate-punctate, instead the dorsum is minutely and usually faintly 
transversely striolate and the sides lack sculpture at least in part 85 

84 Larger species, HW 0-38-0-46, SL 0-33-0-38, AL 0-50-0-54; CI 88-92. (Zaire, Central 

African Republic, Uganda) malatu (p. 399) 

— Smaller species, HW 0-34, SL 0-30, AL 0-40; CI 81. (Zaire) affabile (p. 375) 

85 Head yellow, alitrunk dark brown, gaster yellow; the colours of the head and alitrunk strongly 

contrasting. (Zaire) epinotale (part; p. 326) 

— Head and alitrunk uniformly yellow or uniformly brown, the gaster approximately the same 

colour or darker; the colours of the head and alitrunk not strongly contrasting 86 

86 Head and alitrunk brown, usually dark brown. (Sudan, Mali, Niger; widespread in Africa 

north of the Sahara Desert and in the Near and Middle East) mayri (part ; p. 326) 

— Head and alitrunk yellow 87 

87 Petiole node in dorsal view subglobular; postpetiole node only slightly broader than long (Fig. 

39). (Pantropical tramp, probably of Indian origin) destructor (part; p. 324) 

— Petiole node in dorsal view transverse, distinctly compressed from front to back and obviously 

much broader than long; postpetiole node, distinctly broader than long (Fig. 40). (Nigeria, 
Ghana, Ethiopia, Uganda, Zaire, Tanzania, Zimbabwe, Botswana, South Africa) 

oscaris (part; p. 326) 

88 Eye in profile drawn out anteriorly into a very long lobe or prominence which projects 

anteroventrally across and down the side of the head, almost extending onto the ventral 
surface of the head. (South Africa) xanthognathum(p. 371) 

— Eye oval to more or less round in profile, not drawn out into a long anteroventrally projecting 

lobe 89 

89 Frontal lobes closely approximated, the posteriormost portion of the clypeus which runs 

between them reduced to a very narrow strip which is only fractionally wider than either of 
the frontal lobes. Dorsum and declivity of propodeum meeting in a pronounced angle (Fig. 
98) 90 

— Frontal lobes farther apart, the posteriormost portion of the clypeus which runs between them 

distinctly much wider than either of the frontal lobes. Dorsum and declivity of propodeum in 
profile rounding together or forming a single continuous curve, not meeting in a pronounced 
angle 91 

90 Petiole and postpetiole very narrow and scale-like in profile, the postpetiole especially 

markedly anteroposteriorly compressed (Fig. 96). In dorsal view the postpetiole dorsum 



SOLENOPSIS GENUS-GROUP 315 

scarcely thicker than the petiole . (Guinea) guineense(p. 426) 

— Petiole and postpetiole not scale-like in profile, the postpetiole nodiform (Fig. 98). In dorsal 

view the postpetiole dorsum distinctly thicker than the petiole. (Guinea, Ivory Coast, 
Ghana, Nigeria, Cameroun) invidium (part ; p. 427) 

91 With the head in profile the eye consisting of a peripheral ring of ommatidia encircling a single 

longitudinal row of ommatidia within the ring 92 

— With the head in profile the eye consisting of a peripheral ring of ommatidia encircling two or 

more longitudinal rows of ommatidia within the ring 97 

92 Promesonotal dorsum with only a single pair of standing hairs, at the pronotal humeri. 

Propodeal dorsum without standing hairs. (Botswana) sryetum(p. 413) 

— Promesonotal dorsum with more than one pair of standing hairs. Propodeal dorsum with at 

least one pair of standing hairs present 93 

93 Dorsum of head brown, varying from medium brown to blackish brown 94 

— Dorsum of head yellow, varying from pale yellow to dingy yellow 95 

94 Head and alitrunk the same shade of brown, species not bicoloured. Anterior clypeal margin 

broadly and evenly convex between the inner points of the mandibular insertions. SI 76-79. 
Maximum diameter of eye 0-16 x HW. (Zaire) inquietum(p. 394) 

— Head brown to blackish brown, the alitrunk lighter, usually yellow so that the species is 

bicoloured. Anterior clypeal margin with a clearly differentiated prominent median section, 
not evenly convex between the inner points of the mandibular insertions. SI 86-94. 
Maximum diameter of eye 0-21-0-24 x HW. (Pantropical tramp-species) tioricola(p. 390) 

95 Maximum diameter of eye 0-23-0-24 x HW. First gastral tergite uniformly yellow. (Zim- 

babwe) shilohense(p. 410) 

— Maximum diameter of eye 0-17-0-19 x HW. First gastral tergite with basal half pale yellow, 

apical half brown 96 

96 Small species with relatively short scapes, HW 0-30, SL 0-22, SI 73. (Ghana) trakeip. 417) 

— Larger species with relatively longer scapes, HW 0-34-0-38, SL 0-28-0-30, SI 79-83. (Kenya, 

South Africa) rotundatum(p. 409) 

97 Larger species with relatively very short antennal scapes, HW 0-72-0-74, SI 73-75. Promeso- 

notum with 20 or more pairs of standing hairs. (Tanzania) iyenasu(p. 394) 

— Smaller species with relatively longer antennal scapes, HW 0-30-0-55, SI 75-110; if SI < 80 

then species is minute with HW at lower end of the range. Promesonotum with fewer than 12 
(usually 3-10) pairs of standing hairs 98 

98 Viewed from behind and slightly above the pronotum transversely almost to quite flat and the 

humeri conspicuously angular. (Ivory Coast, Ghana, Nigeria, Camerou, Zaire, Angola) 

egens(p. 385) 

— Viewed from behind and slightly above the pronotum transversely evenly shallowly convex and 

the humeri evenly broadly rounded 99 

99 Strikingly bicoloured species with alitrunk , petiole and postpetiole black to blackish brown , the 

head and its appendages, gaster and legs clear yellow. (Kenya) mirandum(p. 401) 

— Colour various shades of yellow, brown or black; usually a uniform single colour and never 

strikingly bicoloured as above 100 

100 In full-face view the antennal scapes, when laid straight back from their insertions, just 

reaching to slightly exceeding the occipital margin (Fig. 61 ). SI 95-1 10 101 

— In full-face view the antennal scapes, when laid straight back from their insertions, failing to 

reach the occipital margin (Figs 62, 63, 70) . SI 75-98 113 

101 Promesonotum in profile with only 3 pairs of standing hairs (Fig. 78). With head in full-face 

view the posterior margins of the eyes distinctly in front of the midlength of the sides. 
(Zimbabwe) binatu(p. 380) 

— Promesonotum in profile with 4 to more than 8 pairs of standing hairs. With head in full-face 

view the posterior margins of the eyes at or very close to the midlength of the sides 102 

102 Verysmallpaleyellowspecies,HW0-30-0-32,SL0-30-0-34 103 

— Either larger yellow species, HW 0-38-0-50, SL 0-38-0-56, or colour conspicuously dark 

brown to black 104 

103 Occipital margin of head broadly and shallowly concave in full-face view. Propodeal spiracle 

minute and pinhole-like. SI 106-107, CI 75-76. (Kenya) speluncarum(p. 411) 

— Occipital margin of head convex in full-face view. Propodeal spiracle conspicuous, not minute 

and pinhole-like. SI 95-100, CI 78-84. (Gabon, Zaire) gabrielense (p. 392) 

104 Colour brown to black. Alitrunk in profile with promesonotum strongly domed-convex (as in 



316 B. BOLTON 

Fig. 76), the highest point at about the midlength. Smaller species, HW 0-32-0-40, SL 
0-32-0-42 105 

— Colour yellow to light brown. Alitrunk in profile with promesonotum quite shallowly evenly 

convex (Figs 64, 65, 67-69, 75), the highest point in front of the midlength. Generally larger 
species, HW 0-38-0-50, SL 0-38-0-56; species in the narrow zone where measurements 
overlap are very distinctly yellow in colour 106 

105 Legs very pale indeed, conspicuously very much lighter than the alitrunk, sometimes virtually 

colourless. HL 0-39-0-42, SL 0-32-0-36, AL 0-44-0-46. (Cameroun, Gabon, Angola) 

draxocum(p. 385) 

— Legs yellowish brown, only slightly lighter than alitrunk, always distinctly coloured. HL 

0-46-0-50, SL 0-39-0-42, AL 0-54-0-58. (Cameroun) noxitum (p. 403) 

106 With alitrunk in dorsolateral view the metanotal groove very narrow and traversed by 

extremely short and inconspicuous cross-ribs. Propodeal spiracle minute and pinhole-like 

(Fig. 75) 107 

— With alitrunk in dorsolateral view the metanotal groove broad and traversed by long sharply 

defined and conspicuous cross-ribs. Propodeal spiracle large and very obvious, not pinhole- 
like (Figs 64, 65, 67-69) 109 

107 Dingy light brown species. Promesonotum with 8 or more pairs of standing hairs dorsally. HL 

0-60-0-63, HW0-48-0-50.( Lesotho) 6evisi(p. 379) 

— Yellow species. Promesonotum with 4-6 pairs of standing hairs dorsally. HL 0-50-0-58, HW 

0-38-0-46 108 

108 Eyes slightly larger, maximum diameter 0-24-0-27 x HW. Scapes relatively shorter, SI 

97-102. (Namibia, Lesotho, South Africa) schultzei(p. 410) 

— Eyes slightly smaller, maximum diameter 0-20-0-23 x HW. Scapes relatively longer, SI 

104-1 10. (South Africa) excensurae(p. 386) 

109 Dorsal surface of propodeum transversely flat or even feebly concave between a pair of blunt 

and ill-defined low longitudinal rims which separate the dorsum proper from the sides. 
(Sudan) kineti{p. 396) 

— Dorsal surface of propodeum transversely convex, or if somewhat flattened then the flattened 

area not bounded by a pair of low longitudinal rims which separate the dorsum proper from 

the sides 110 

110 Promesonotal dorsum with 4-6 pairs of standing hairs Ill 

— Promesonotal dorsum with 8 or more pairs of standing hairs 112 

111 With alitrunk in profile the metanotal groove forming a very broad shallow U-shaped trough 

(Fig. 69). Propodeal dorsal outline behind the metanotal groove convex and rounded, the 
dorsum rounding evenly into the declivity so that the two surfaces form a single smooth 
convexity. (Ethiopia) crawleyi(p. 383) 

— With alitrunk in profile the metanotal groove shallowly impressed, not forming an extensive 

U-shaped trough (Fig. 65). Propodeal dorsal outline behind the metanotal groove consisting 
of a more or less flat posteriorly-sloped zone which then rounds quite abruptly into the more 
steeply sloping declivity, the two surfaces not forming a single smooth convexity. (Sudan, 
Kenya) arboreum (p. 377) 

112 Subpetiolar process a conspicuous lobe (Fig. 67). With the head in full-face view the sides 

behind the eyes with all hairs decumbent to appressed. SL 0-50-0-56. (Zimbabwe) 

firmum(p. 387) 

— Subpetiolar process a low ridge (Fig. 68). With the head in full-face view the sides behind the 

eyes with all hairs suberect to subdecumbent. SL 0-39-0-48. (Zimbabwe, Rwanda) vecte(p. 419) 

113 Propodeal spiracle with a large circular orifice which is very conspicuous and dominates the side 

of the propodeum (Fig. 66) 1 14 

— Propodeal spiracle with a small or minute circular orifice which usually appears as a pinhole in 

the side of the propodeum (Figs 74-90) 119 

114 Median clypeal carinae terminating at anterior clypeal margin in a pair of elongate subspini- 

form teeth which are usually somewhat curved towards the midline and which project out 

over the mandibles (Fig. 73) . (Sierra Leone , Guinea) occidentale(p. 404) 

— Median clypeal carinae terminating at anterior clypeal margin in a pair of short broad 

triangular denticles or merely a pair of acute or blunt angles; without elongate teeth which 
project out over the mandibles ; 1 15 

115 Median portion of clypeus with its anterior free margin convex between the points of 

termination of the clypeal carinae; the carinae themselves low, rounded and poorly defined, 






SOLENOPSIS GENUS-GROUP 317 

and their points of termination not prominent. (South Africa) kelapre(p. 395) 

— Median portion of clypeus with its anterior free margin concave between the points of 

termination of the clypeal carinae; the carinae themselves conspicuous and their points of 

termination prominent as denticles or projecting angles 116 

116 Head and body yellow 117 

— Head and body brown 118 

117 Nodes of both petiole and postpetiole high and narrow in profile , the postpetiole with a flat and 

vertical anterior face. SI 88-93. (Gabon , Zaire) captator(p. 382) 

— Nodes of petiole and postpetiole not high and narrow in profile, the postpetiole without a flat 

and vertical anterior face. SI 79-85. (Tanzania, Botswana, Zimbabwe) /ene(p. 397) 

118 Dorsal alitrunk with only 4 pairs of standing hairs, of which 3 pairs are on the promesonotum 

and lpaironthepropodeum. SI 90-93. (Angola) borlei(p. 381) 

— Dorsal alitrunk much more densely hairy, the promesonotum very obviously with more than 3 

pairs and the propodeum with more than 1 pair of standing hairs (Fig. 66). SI 83-86. (Sudan, 
Kenya, Zaire) leopoldinum (p. 397) 

119 Anterior and posterior faces of both petiole and postpetiole meeting in a sharp rim or edge 

which is continuous around the sides and dorsum of each node. Body colour glossy black. 
(Ghana) vonatu (p. 420) 

— Anterior and posterior faces of both petiole and postpetiole not meeting in a sharp continuous 

rim or edge, the two surfaces either rounding bluntly together or the petiole with a slight 
lateral rim which does not run onto the dorsum. If the latter then colour yellow 120 

120 Eyes relatively very large, the maximum diameter 0-30 x HW or more. In general the 

maximum length of the eye in profile is markedly greater than the distance from the 
anteriormost point of the eye to the closest point of the mandibular articulation (Figs 72, 74) 121 

— Eyes relatively smaller, the maximum diameter <0-30 x HW. In general the maximum length 

of the eye in profile is usually distinctly less than the distance from the anteriormost point of 
the eye to the closest point of the mandibular articulation , but in a few species the two lengths 
may be about equal or the former fractionally greater than the latter 124 

121 Uniformly dark brown to blackish brown species 122 

— Uniformly yellow to light brownish yellow species 123 

122 Promesonotal dorsum with 8-10 pairs of standing hairs. Longest hairs projecting from first 

gastral tergite distinctly longer than maximum diameter of eye. (Burkina Faso)... balathir(p. 378) 

— Promesonotal dorsum with 3-4 pairs of standing hairs. Longest hairs projecting from first 

gastral tergite distinctly shorter than maximum diameter of eye. (Kenya) manir(p. 400) 

123 Pronotum, mesonotum and propodeum each with a single pair of standing hairs, so that the 

alitrunk has only 3 pairs in total on the dorsum (Fig. 74). (Namibia) katir(p. 395) 

— Pronotum, mesonotum and propodeum each with more than one pair of hairs, so that the 

alitrunk very obviously has more than 3 pairs in total on the dorsum. (Kenya) holothir(p. 393) 

124 With the head in full-face view the eyes at or only fractionally in front of the midlength of the 

sides 125 

— With the head in full-face view the eyes distinctly in front of the midlength of the sides 126 

125 MaximumdiameterofeyeO-17-0-18xHW. SI 86-88. (Ghana) tanysum (p. 416) 

— Maximum diameter of eye 0-24 x HW. SI 92. (Tanzania) disoriente(p. 383) 

126 Projecting median portion of clypeus with its anterior margin concave , the concavity flanked by 

a pair of triangular prominences or denticles (at the apices of the clypeal carinae) , this pair of 
prominences separating the anterior and lateral margins of the projecting median section of 
the clypeus (Fig. 62). Clypeal carinae always sharply and strongly developed, widely 
divergent anteriorly 127 

— Projecting median portion of clypeus with its anterior margin transverse to feebly concave , the 

anterior margin rounding bluntly into the lateral margins or with an obtuse angle between 
them, but without a pair of triangular prominences or denticles separating the anterior and 
lateral margins of the projecting median section of the clypeus. Clypeal carinae variably 
developed, sometimes vestigial, sometimes sharp but almost parallel, sometimes widely 
divergent anteriorly 133 

127 In profile the petiole and postpetiole nodes low, not anteroposteriorly compressed; the former 

subconical and the latter subglobular so that the summit of the postpetiole is much more 
broadly rounded than that of the petiole (shape approximately as in Figs 77-81) 128 

— In profile the petiole and postpetiole nodes high and narrow, anteroposteriorly compressed; 

the summit of the postpetiole almost as narrowly rounded as that of the petiole and the 



318 B. BOLTON 

anterior face of the postpetiole vertical or nearly so (Figs 84-88) 129 

128 Promesonotal dorsum with 6-7 pairs of standing hairs. Maximum diameter of eye 0-27 x HW. 

CI 74. (Kenya) rastractum (p. 406) 

— Promesonotal dorsum with 3-4 pairs of standing hairs. Maximum diameter of eye 0-21-0-23 x 

HW. CI 77-80. (Zimbabwe) springvalense(p. 412) 

129 With the propodeum in profile the spiracle relatively high on the side and close to the dorsal 

outline . Dorsum and declivity of propodeum confluent and forming a single sloping surface , 
the two not separated by a rounded angle (Fig. 84). In dorsal view the propodeal spiracles 
widely separated and prominent, each orifice situated at the apex of a tubercle. (Zaire) 

angustinode(p. 376) 

— With the propodeum in profile the spiracle relatively low on the side , widely separated from the 

dorsal outline. Dorsum and declivity of propodeum not confluent, the two surfaces sepa- 
rated by a rounded angle (Figs 85-88). In dorsal view the propodeal spiracles not widely 
separated nor prominent, not located at the apices of tubercles 130 

130 Eyes large, maximum diameter 0-26-0-28 x HW. Propodeal spiracle very small, reduced to a 

minute spot (Fig . 88) . (Botswana) fugelanum (p. 391 ) 

— Eyes smaller, maximum diameter 0-20-0-24 x HW. Propodeal spiracle small but still distinctly 

present and circular (Figs 85-87) 131 

131 Species combining relatively long scapes with small eyes, SI 95-98 and maximum diameter of 

eye 0-20-0-22 x HW. HW 0-40-0-41 and summit of petiole usually with a narrow crest 
towards the sides (Fig. 86) . (Zimbabwe) arnoldi(p. 378) 

— Species combining relatively short scapes with larger eyes, SI 87-95 and maximum diameter of 

eye 0-22-0-24 x HW. HW outside above range, either ca 0-37 or 0-42-0-44 and summit of 
petiole without a narrow crest towards the sides (Figs 85, 87) 132 

132 Promesonotum with 5 pairs of standing hairs. SI 87-89, CI 77, HW 0-37 (Fig. 85). (Congo, 

Zaire) a!tinode(p. 375) 

— Promesonotum with 7-8 pairs of standing hairs. SI 90-95, CI 78-81, HW 0-40-0-44 (Fig. 87). 

(Angola) tynsorum(p. 417) 

133 Subpetiolar process a large keel-like translucent lamella (Fig. 90). (South Africa) lubricum(p. 398) 

— Subpetiolar process a low ridge , narrow flange or small lobe , or virtually absent 134 

134 Larger species with dimensions in range SL 0-32-0-44, HL 0-46-0-60, HW 0-35-0-50 135 

— Smaller species with dimensions in range SL 0-24-0-29, HL 0-40-0-45 , HW 0-30-0-35 141 

135 Dark brown species. Clypeal carinae vestigial to absent and the anterior clypeal margin evenly 

broadly convex, without a differentiated projecting central portion (Fig. 63). (South Africa) 

boerorum(p. 381) 

— Yellow to brown species. Clypeal carinae well developed and the anterior clypeal margin with a 

differentiated projecting central portion, not evenly broadly convex. If colour brown then 
anterior clypeal margin concave medially 136 

136 Eyes relatively small, the maximum diameter 0-18-0-20 x HW. Range of other dimensions, 

HW 0-42-0-50, CI 79-83, SL 0-36-0-44, SI 80-90 137 

— Eyes averaging larger, the maximum diameter 0-20-0-25 x HW. Range of other dimensions, 

HW 0-35-0-42, CI 73-78, SL 0-32-0-40, SI 89-98. If HW > 0-40 and SL > 0-36 then the 
scapes are longer (SI 95-98) and the eyes are larger (0-24-0-25 x HW) 138 

137 Petiole shaped as in Fig. 81, with a small narrow ventral process. Metanotal groove deeply 

impressed and broad, traversed by long cross-ribs. Anteriorly projecting median portion of 
clypeus narrow, the carinae close together and only feebly divergent anteriorly. Yellow 
species. (South Africa) rhopalocerum(p. 407) 

— Petiole shaped as in Fig. 89, with a larger deeper ventral process. Metanotal groove shallowly 

impressed and narrow, with short cross-ribs. Anteriorly projecting median portion of 
clypeus broad, the carinae wide apart and broadly divergent anteriorly. Brown species. 
(South Africa) pater num (p. 405) 

138 Petiole node in profile high and narrow, the anterior face distinctly concave and the posterior 

convex (Fig. 80). HW 0-40-0-42, SL 0-39-0-40, SI 95-98; maximum diameter of eye 
0-24-0-25 xHW. (South Africa) tablense(p. 414) 

— Petiole node in profile broad, the anterior and posterior faces about equally sloped, the former 

not concave (Figs 77, 79). HW0-35-0-39,SL0-32-0-35, SI 89-94; maximum diameter of eye 
0-20-0-23 xHW 139 

139 With alitrunk in profile the metanotal groove scarcely impressed and the promesonotal dorsum 

sloping gradually to the site of the groove, the promesonotum and propodeum not forming a 



SOLENOPSIS GENUS-GROUP 319 

pair of sharply separated convexities. (Zimbabwe) nuptualis(p. 403) 

— With alitrunk in profile the metanotal groove broad and deep so that the promesonotum and 

propodeum form a pair of sharply separated convexities (Figs 77, 79) 140 

140 Petiole node in profile low and more bluntly rounded above; outline shape of alitrunk and 

petiole as Fig. 79. Promesonotal dorsum with 3 pairs of standing hairs. (Zimbabwe) 

symmotu(p. 414) 

— Petiole node in profile higher and conical, narrowly rounded above; outline shape of alitrunk 

and petiole as Fig. 77. Promesonotal dorsum with 4 or more pairs of standing hairs. (South 
Africa) exchao(p. 387) 

141 Promesonotum with a single pair of standing hairs, situated at the humeral angles. Petiole node 

very low and broadly rounded, subglobular, the peduncle with a minute inconspicuous 
anteroventral process. (South Africa) braunsi(p. 382) 

— Promesonotum with 3-5 pairs of standing hairs. Petiole node subconical, the peduncle usually 

with a small but distinct anteroventral process 142 

142 Median projecting portion of anterior clypeal margin forming a sharply defined subrectangular 

prominence in full-face view. (Ethiopia) pallidipes(p. 405) 

— Median projecting portion of anterior clypeal margin rounded, not forming a sharply defined 

subrectangular prominence in full-face view 143 

143 Minute species with small eyes, HL 0-38-0-40, HW 0-30-0-32, SL 0-24-0-25; maximum 

diameter of eye 0- 19 x HW. (South Africa) ma vide(p. 400) 

— Larger species with larger eyes, HL 0-42-0-45, HW 0-32-0-35, SL 0-26-0-28; maximum 

diameter of eye 0-20 x HW or more 144 

144 Uniformly yellow species with SI 81-84 and maximum diameter of eye 0-22-0-24 x HW. 

(South Africa) musicum(p. 402) 

— Uniformly dark brown species with SI 76-80 and maximum diameter of eye 0-20-0-21 x HW. 

(South Africa) torvicte(p. 416) 

145 Dorsal alitrunk without standing hairs. (Lesotho) guillarmodi(p. 392) 

— Dorsal alitrunk with one or more pairs of standing hairs 146 

146 In full-face view the antennal scapes, when laid straight back from their insertions, surpassing 

the occipital margin; SI 95-102. (Gabon, Zaire, Uganda, Central African Republic, 
Tanzania) strangulatum{p . 413) 

— In full-face view the antennal scapes, when laid straight back from their insertions, conspi- 

cuously failing to reach the occipital margin ; SI usually <95 147 

147 Head, alitrunk and gaster glossy dark brown, the legs off-white and with a bleached appear- 

ance , contrasting very strongly with the dark body. (Gabon) spectrum (p. 41 1) 

— Head and body variously coloured but never dark brown contrasting with bleached-white legs 148 

148 Petiole in profile with a high sharply wedge-shaped node and a very short anterior peduncle; 

subpetiolar process relatively large. Postpetiole node high and somewhat anteroposteriorly 
compressed, narrowly rounded above. (Ivory Coast, Ghana, Cameroun) dolatu(p. 384) 

— Petiole in profile either not high and wedge-shaped or with an elongate anterior peduncle, or 

both. Subpetiolar process variable but postpetiole node low and not anteroposteriorly 
compressed 149 

149 In profile the postpetiole node as large as or only fractionally smaller than the petiole node. 

Posterior face of postpetiole node in profile with a long shallow slope (Fig. 92) . SI 85-95 150 

— In profile the postpetiole node distinctly much smaller than the petiole node, or the posterior 

face of the postpetiole node in profile not a long shallow slope, or usually both. SI 74-87 152 

150 Blackish brown to jet black species. (Senegal, Ghana, Nigeria, Zaire, Kenya) rosae(p. 408) 

— Yellowish brown to light brown species 151 

151 Nodes of petiole and postpetiole in dorsal view broader than long. HL 0-46-0-48, SL 

0-32-0-34, CI 78-82, SI 87-92. (Zimbabwe) pulchrum (p. 406) 

— Nodes of petiole and postpetiole in dorsal view longer than broad. HL 0-50, SL 0-36, CI 76, SI 

95. (Zaire) bequaerti(p. 379) 

152 Pronotal dorsum with a pair of long erect hairs at the humeri, without a similar pair of hairs on 

the anterior pronotal margin between the humeral pair 153 

— Pronotal dorsum with a pair of long erect hairs at the humeri , also with a similar pair of hairs on 

the anterior pronotal margin between the humeral pair 155 

153 Somewhat larger brown species, HW 0-34-0-38, SL 0-28-0-31, PW 0-23-0-26 (CI 80-83). 

With eye in profile the outer ring of ommatidia enclosing either 3 longitudinal rows of 
ommatidia, or enclosing 2 rows plus a few other ommatidia. (South Africa) taedium(p. 415) 



320 B. BOLTON 

— Somewhat smaller yellow species, HW 0-26-0-33, SL 0-20-0-28, PW 0-16-0-21 (CI 72-79). 

With eye in profile the outer ring of ommatidia enclosing only a single longitudinal row of 
ommatidia , or enclosing at most a single row plus a couple of other ommatidia 154 

154 Minute species, HW 0-26-0-30 (CI 72-76), SL 0-20-0-26, PW 0-16-0-19. Head capsule in 

profile markedly depressed, the ventral surface flat and not more convex than the dorsal. 
(Ethiopia, Sudan, Kenya, Zimbabwe, Angola, Namibia) mictilis(p. 401) 

— Slightly larger species, HW 0-32-0-33 (CI 76-79), SL 0-26-0-28, PW 0-20-0-21. Head capsule 

in profile not markedly depressed, the ventral surface convex, usually more convex than the 
dorsum. (South Africa) fastidium(p 389) 

155 Anterior half of pronotal dorsum with a clump of 4 or more pairs of standing hairs. (Nigeria, 

Kenya, Zaire , Botswana, South Africa) vaguum(p. 418) 

— Anterior half of pronotal dorsum lacking a clump of 4 or more pairs of standing hairs; usually 

with only the anteromedian and humeral pairs present but sometimes the pronotum with a 
third pair set farther back. (Ethiopia, Kenya, Zimbabwe, Ivory Coast, Ghana, Nigeria, 
Cameroun, Gabon, Zaire) exiguum (p. 388) 

The scabriceps-group 

(Figs 19-21, 26, 31-33) 

Worker. Polymorphic with marked variation in size (HW ca 0-60->2-60 in the group), showing 
monophasic allometric variation. Palp formula 2,2 (glabrum, abyssinicum, scabriceps, dentigerum). 
Mandibles massive and strongly curved, with rugulose to coarse rugose sculpture; trulleum open and 
relatively large. Mandibles armed with 3 or 4 teeth, when 4 the basalmost is reduced to a minute offset 
denticle or even a blunt angle. Raised median portion of clypeus weakly to acutely bicarinate, the carinae 
outcurved or strongly divergent anteriorly. Median portion of clypeus short, not projecting forwards 
anteromedially, the margin of the median portion concave. Anterior clypeal margin armed with a pair of 
teeth or tubercles. Posteriorly the median portion of the clypeus broader than either of the frontal lobes 
where it passes between them. Cephalic dorsal sculpture variable but lateral portions of the clypeus, the 
area immediately behind the clypeus, and the area around the antennal fossae with striolate or costulate 
sculpture present (less distinct in smaller workers). Side of head between mandibular base and eye usually 
longitudinally striate or costulate. Eyes small to moderate, always with more than two ommatidia, situated 
at or slightly in front of the midlength of the sides. Eyes not markedly oblique with respect to the long axis 
of the head, and never reniform. Head short and broad, CI 86-100 in abyssinicum and may exceed CI 100 
elsewhere in the group; CI increases with increased worker size. Scapes with SI 55-110 {abyssinicum), 
decreasing in relative length with increased body size. Antennae 12-segmented, without a strongly 
differentiated club. Either the funicular segments gradually increase in size apically or the terminal 3-4 
segments form a weakly defined club. Standing pilosity present or absent on dorsal alitrunk and gaster. 
Propodeal dorsum sculptured, the sculpture usually transverse but sometimes disorganized or faint. 
Propodeal spiracle an elongate ellipse or short slit, orientation of its orifice vertical or nearly so. 
Propodeum rounded to bluntly angular between dorsum and declivity. Petiolar spiracle on the peduncle, 
usually at or close to its midlength. (Workers examined: abyssinicum, glabrum, criniceps, scabriceps, 
dentigerum, plus two indeterminate species.) 

Female. Size only slightly greater than that of the largest conspecific worker but female head smaller and 
gaster larger than in largest worker. Characters generally as worker but CI tending to be 100 or more. 
Ocelli present and eyes larger than in conspecific worker. Alitrunk with full complement of flight sclerites 
and alate when virgin. HW about equal to the maximum width of the mesoscutum or greater, the latter as 
long as or slightly longer than broad. Parapsidal furrows long and distinct. Pronotum not forming a part of 
the dorsal alitrunk but in dorsal view visible as a narrow anterior collar. Axillae linked by glossy thin 
cuticle, appearing to extend across the entire width of the dorsum. Propodeal spiracle usually more ovate 
than in workers, less obviously slit-like . Forewings with cross-vein m-cu present or absent. In some females 
m-cu present on one wing but absent from the other. (Females examined: abyssinicum, criniceps, glabrum, 
scabriceps.) 

Male. Very much smaller than conspecific female. Mandibles narrow and bidentate or with an additional 
minute basal denticle. Palp formula 2,2 (abyssinicum, criniceps, one indeterminate species). Antennae 
13-segmented and whip-like, the scape extremely short and globular to subglobular, the first funicular 
segment globular, the remaining funicular segments tapering to the apex. Eyes large and situated far 
forward on the sides, their anterior margins touching or even slightly overlapping the clypeus (Fig. 26). 



SOLENOPSIS GENUS-GROUP 321 

Sides of head behind eyes relatively long and forming a sort of turret which accommodates the very large 
ocelli. In full-face view the ocelli break the outline of the occipital margin. Head not much broader behind 
the eyes than in front of them and the maximum head width much less than the width of the mesoscutum. 
Sculpture of head feeble to virtually absent. Pronotum not present on dorsal alitrunk, the mesoscutum 
broader than long to slightly longer than broad. Notauli absent and parapsidal furrows faint to vestigial. 
Mesoscutellum broader than long, axillae extending right across dorsum as in females. Propodeum very 
broad in dorsal view and the spiracle far forward. Alitrunk unsculptured. Venation as in female. Genitalia 
partially exserted, not bizzarly modified. (Males examined: abyssinicum, criniceps, glabrum, scabriceps .) 

A small group of very distinctive ground-nesting polymorphic species which are strictly granivorous 
(Rothney, 1889; Bingham, 1903), and which contains some of the largest species included in Monomorium 
(worker TL up to 8-0). Most described species are confined to the Oriental region {criniceps (Mayr), 
glabrum (Andre), muticum (Emery), rogeri (Mayr), scabriceps (Mayr), and perhaps wroughtonianum 
Ettershank), but there is a single species in the Palaearctic region around the eastern Mediterranean 
{dentigerum (Roger)) and a single representative of the group in the Afrotropical region (abyssinicum) 
which is distributed throughout the Sahelian zone. 

Members of this group were regarded as constituting a separate genus (Holcomyrmex) by Bingham 
(1903) and earlier workers, the species being separated from Monomorium by their lack of a strongly 
defined antennal club and polymorphic workers. Following Emery's (19086) reduction of Holcomyrmex to 
a species-group of Monomorium, both Wheeler (1922) and Emery (1922) treated Holcomyrmex as a 
subgenus of Monomorium, defining it by saying that the worker antennal club was short and poorly 
defined, the workers were strongly dimorphic, aud that the male antennae consisted of a short scape, 
globular first funicular segment, and rapidly tapering remainder of the funiculus. These males are in fact 
the same as those of the closely related destructor-group (see p. 323). Ettershank (1966) did not consider 
these characters consistent enough or sufficiently strong to maintain Holcomyrmex as separate, even at 
subgenus level. He relegated the name to the synonymy of Monomorium, where it remains today. 

Emery's (1922: 181) catalogue of scabriceps-group members includes a couple of names which should be 
excluded from the group. M. whitei Wheeler, from Australia, which belongs to a peculiarly Australian 
group of granivores, and evansi Donisthorpe from Iraq. Ettershank (1966) placed whitei in Chelaner but 
left evansi in the scabriceps-group. Superficially the workers of evansi are similar to those of the 
scabriceps-group but these similarities are certainly convergently acquired. M. evansi workers differ from 
scabriceps-group members by being monomorphic, lacking allometric variation in such ratios as SI : HW. 
The strongly bidentate clypeus of evansi is prominent medially, rather than reduced and short as in 
scabriceps and allies, and the eyes are elongate ellipsoid. The antennal club of evansi is strongly defined, 
the propodeal spiracle is circular and the propodeum unsculptured dorsally. The petiolar spiracle is at the 
node rather than near the midlength of the peduncle. The very large male of evansi, which is almost as large 
as the female and very much larger than the workers, bears no resemblance to males of the scabriceps- 
group. It appears to be a very specialized derivative from the salomonis-setuliferum line but with many 
unique modifications including broad blade-like powerful bidentate mandibles and a greatly expanded 
plate-like final gastral tergite which is strongly reflexed ventrally. 

The species-group closest related to the scabriceps-group is the destructor-group. Males of the two have 
identical diagnostic characters at species-group level but in females and workers destructor-group members 
have the anterior clypeal margin unarmed and have the propodeal spiracle circular. 

Monomorium abyssinicum (Forel) 

(Figs 31-33) 

Holcomyrmex abyssinicus Forel, 1894a: 83. Syntype workers, Ethiopia: 'Sudabessinien' (Ilg) (MHN) 

[examined]. 
Monomorium (Holcomyrmex) abyssinicum (Forel) Forel, 1910c: 250. 

Worker. TL 2-6-6-7, HL 0-68-2-04, HW 0-60-1-94, CI 86-100, SL 0-50-1-06, SI 55-110, PW 0-38-0-90, 
AL 0-72-1-74 (40 measured). 

Workers in any series showing remarkable size variation and exhibiting simple monophasic allometry. 
Mandibles longitudinally rugose, armed with 3 teeth; sometimes also with a minute offset basal denticle or 
blunt angle following the basal tooth. In larger workers the 3 teeth sometimes blunted or worn away. 
Anterior clypeal margin concave medially between a pair of prominent teeth which are situated on the 
margin in front of the antennal insertions. These teeth tend to be relatively larger, longer and more acute in 
small workers than in large ones. Eyes set slightly in front of the midlength of the sides, the maximum 



322 B. BOLTON 

diameter of the eye 0-14-0-24 x HW; the relative size of the eye decreasing with increased head size. 
Relative length of scape decreasing with increased head size, as follows. 

When HW < 0-70 then SI is >90; 

when HW 0-70-1-00 then SI 88-75; 

when HW 1-00-1-30 then SI 75-66; 

when HW 1-30-1-60 then SI 66-58; 

when HW l-60->l-90 then SI 58-55. 
In large workers the head in full-face view with the sides approximately straight and more or less parallel; in 
small workers the sides of the head diverging anteriorly. With alitrunk in profile the metanotal groove 
impressed. Propodeal spiracle a vertical or near-vertical ellipse of slit. Petiolar peduncle with a conspicu- 
ous anteroventral process which when best developed consists of a triangular lamella followed by a broad 
flange. This process varies considerably in shape and size between series, and between differently sized 
members of the same series. At its most reduced the process appears as an elongate flange with a rounded 
anteroventral angle. Petiolar spiracle at or close to the midlength of the peduncle. Elongate standing hairs 
sparse on cephalic dorsum in large workers, may be absent in smallest individuals. Entire dorsum of head 
with short decumbent to appressed pubescence, relatively sparse and directed towards the midline. Dorsal 
alitrunk with numerous standing hairs in largest workers but these may be absent from the propodeum in 
small workers. In the very smallest individuals the promesonotum may also lack standing hairs. Petiole, 
postpetiole and gaster with sparse backward directed hairs and with decumbent to appressed moderately 
dense pubescence. Dorsum of head behind the costulate or rugulose clypeal region utterly smooth and 
featureless between scattered hair-pits. In all workers except the very smallest the area on the side of the 
head between the eye and the clypeus with longitudinal costulae or rugulae. Promesonotal dorsum 
longitudinally rugulose or with disorganized rugulae, to smooth. Sometimes with a few widely scattered 
punctulate patches or faint rugular vestiges. In general larger workers are more strongly sculptured than 
smaller workers. Propodeal dorsum transversely to obliquely rugulose in large to medium workers, the 
rugulae becoming weak and irregular with reduced size, almost obliterated in the smallest. In the range 
from largest to smallest workers punctate sculpture usually becomes more apparent with decreasing size on 
the propodeal dorsum. Sides of alitrunk sculptured, again the density and intensity diminishing with 
decreasing size. First gastral tergite unsculptured in all sizes. Colour varying between series and between 
individuals of different sizes in the same series. Large to medium workers varying from reddish brown to 
dark brown with a reddish tint, sometimes with reddish black areas on the head and alitrunk. Gaster darker 
than head and alitrunk, usually blackish brown to black. Smallest workers much lighter in colour, with the 
head and alitrunk dull yellowish brown to light brown and the gaster darker in shade. 

This very conspicuous species ranges across the entire Sahelian zone of the Afrotropical region. Apart 
from the fact that it is granivorous and nests in the ground, nothing is known of its biology. 

Material examined 

Ethiopia: no loc. (//g). Sudan: Kadugli area (C. Sweeney). Burkina Faso; Ougadougou (P. Room). 
Ghana: Amfeda (C. A. Collingwood). Nigeria: Mokwa (C. Longhurst). 

The destructor-group 

(Figs 19-21, 26, 34, 35, 39-41) 

Worker. Monomorphic to weakly polymorphic, usually with marked variation in worker size and 
frequently exhibiting monophasic allometry. Mandibles usually sculptured, sometimes smooth; may be 
less distinctly sculptured in small than in large workers. Trulleum relatively large and open, only narrowly 
so in some. Mandibles usually with 4 teeth, less commonly with 3. When 4-dentate the basal tooth is 
reduced to a minute offset denticle or small angular prominence which is usually distinctly separated from 
the three main teeth; denticle sometimes lost in smallest workers. Palp formula 2,2. Anterior clypeal 
margin unarmed, without a pair of projecting teeth. Median portion of clypeus raised, weakly longitudi- 
nally bicarinate to rounded, the carinae or rounded edges broadly divergent anteriorly. Median portion of 
clypeus not sharply projecting forward anteromedially, its free margin shallowly convex to broadly 
concave. Posteriorly the median portion of the clypeus is broader than either of the frontal lobes where it 
passes between them. Eyes relatively small but distinct (maximum diameter 0-13-0-20 x HW), situated in 
front of the midlength of the sides and never reniform. Sculpture of cephalic dorsum variable. Lateral 
portions of clypeus, area immediately behind clypeus and area around antennal fossae with fine striae or 
costulae ; all sculpture fainter in smaller individuals . Head relatively short and broad (CI 80-97) , the scapes 
short (SI 78-89). In weakly polymorphic species the scapes of smaller workers are relatively longer than 
those of larger individuals, and in larger workers the scapes when laid straight back from their insertions 



SOLENOPSIS GENUS-GROUP 323 

fall far short of the occipital margin. Antennae with 12 segments, with a strongly differentiated apical club 
of 3 or rarely 4 segments. Propodeal dorsum usually transversely sculptured even if only feebly so, 
sometimes the transverse pattern masked or replaced by dense punctation. Dorsal alitrunk and gaster with 
numerous standing hairs present. Propodeal spiracle circular to subcircular and the propodeum rounded 
between dorsum and declivity. Petiolar spiracle at or immediately in front of the anterior face of the node. 
Venom of sting lacking alkaloids. (Workers examined: all included in this study plus lameerei, chobauti, 
santschianum, aberrans.) 

Female. Larger than largest conspecific worker, most characters as worker. Head with larger eyes and with 
ocelli present. Alitrunk with full complement of flight sclerites, alate when virgin. HW slightly less than to 
slightly greater than the width of the mesoscutum, the latter as long as broad or slightly longer than broad. 
Pronotum not forming part of dorsal alitrunk, visible as a narrow collar anteriorly. Parapsidal furrows faint 
to vestigial. Axillae forming a continuous strip of thin cuticle across the width of the dorsum. Wings with 
cross-vein m-cu usually absent, only rarely present. (Females examined: destructor, emeryi, mayri, 
oscaris.) 

Male. Very much smaller than conspecific female. Mandibles narrow and with 2-3 teeth. Palp formula 
2,2. Antennae 13-segmented and whip-like, the funicular segments after the first tapering apically. Scape 
very short, only fractionally longer than broad, or subglobular to globular; first funicular segment globular 
(Fig. 26). Eyes very large, situated far forward on the sides, their anterior margins in contact with the 
lateral portions of the clypeus or even slightly overlapping them. Sides of head behind eyes long and 
forming a turret which accommodates the very large ocelli. In full-face view the ocelli break the occipital 
margin outline. Head not much broader behind eyes than in front of them and maximum head width much 
less than width of the mesoscutum. Head and alitrunk not predominantly reticulate-punctate nor 
shagreenate everywhere. Notauli absent from mesoscutum and parapsidal furrows faint. Axillae extending 
across dorsum as a continuous thin cuticular strip. Venation as female. Genitalia partially exserted, not 
bizarrely modified. (Males examined: destructor, emeryi, mayri, oscaris, chobauti, santschianum.) 

With 6 species represented in the Afrotropical region and several extralimital members in the Palaearctic 
and Oriental regions, the destructor-group forms the core of the old subgenus Parholcomyrmex . The 
members of the group are mostly predators and scavengers though one peripheral species, chobauti, is a 
granivore. 

Most of the Afrotropical species now included in the destructor-group appear under Parholcomyrmex in 
Wheeler's (1922: 873) catalogue in one form or another, but oscaris and emeryi are conspicuous by their 
absence, having been placed in Monomorium s.str. by Wheeler despite the fact that Arnold (1916) had 
pointed out that emeryi had a male characteristic of this group (Arnold (1944) later shifted emeryi into the 
group), and Forel (1894a) had stated that oscaris was close to destructor. 

A couple more corrections to the catalogue, as regards this group, are as follows. M. amblyops Emery, a 
name figuring in Wheeler's catalogue, is a South American species correctly referred to the genus 
Tranopelta. Forel (1914, 1916) mistakenly appended some African Monomorium as infraspecific forms of 
this species, to which they are not at all related. 

M. australe was transferred into the destructor-group by Santschi (1917) based on a misidentification of 
australe and his mistaken association of australe with havilandi. It was retained in the destructor-group by 
both Wheeler (1922) and Emery (1922), but it is now known that neither australe nor havilandi is correctly 
placed here. The former belongs in the salomonis-group and the latter in the setuliferum-group. 

The Afrotropical species fall into two complexes, the first of which (including emeryi and robustior) does 
not show marked monophasic allometric variation in the worker caste but which may {robustior) or may 
not {emeryi) have conspicuous size variation in any worker series. The second complex, which contains 
destructor, oscaris, epinotale and mayri, shows marked monophasic allometric variation in the worker caste 
and exhibits conspicuous size variation in any worker series. 

At species-group level the destructor-group is very close to the scabriceps-group and the two probably 
shared a common ancestor in the relatively recent past. The very characteristic males are identical in both 
groups but female castes are separated by the presence of clypeal teeth and an elliptical or slit-shaped 
propodeal spiracle in the scabriceps-group. 

Recent work by Jones et al. (1982) and Blum et al. (1985) indicates that only the destructor-group of 
Monomorium lacks alkaloids of any form as a fraction of the sting venom but has phenol and salicylalde- 
hyde, fractions not previously known in ants. Relatively few species of this very large genus have been 
investigated for venom constituents as yet, but these studies may provide much new information 
concerning the relationships of various species-groups within the genus. For a synopsis of what is known of 
the chemical components of ant venoms see Blum (1985). 



324 B. BOLTON 

Monomorium destructor (Jerdon) 

(Fig. 39) 

Atta destructor Jerdon, 1851: 105. Syntype workers, India (T. C. Jerdon) (no types known to exist). 
Myrmica ominosa Gerstacker, 1858: 263. Syntype workers, 'East Africa', no further data (no types known 

to exist). [Synonymy by Dalla Torre, 1893: 66.] 
Myrmica atomaria Gerstacker, 1858: 263. Syntype workers, 'East Africa', no further data (no types known 

to exist). [Synonymized with ominosa by Roger, 1863ft: 31.] 
Myrmica basalis Smith, 1858: 125. Syntype workers, Sri Lanka (BMNH) [examined]. [Synonymy by 

Forel, 1894: 86.] 
Myrmica gracillima Smith, 1861a: 34. Holotype worker, Israel (Hooker & Hanbury) (not in BMNH or 

UM, presumed lost). Syn. n. 
Myrmica vexator Smith, 18616: 47. Syntype workers, Indonesia: Ternate I., no. 21 (A. R. Wallace) (UM) 

[examined]. [Synonymy by Donisthorpe, 1932: 468.] 
Monomorium destructor (Jerdon) Dalla Torre, 1893: 66. 

Worker. TL 1-8-3-5, HL 0-50-0-88, HW 0-40-0-79, CI 76-92, SL 0-41-0-56, SI 70-104, PW 0-23-0-45, 
AL 0-54-0-92 (55 measured). 

Workers showing marked size variation in any given series, and displaying monophasic allometric 
variation. Mandibles with 3 strong teeth, the fourth (basal) reduced to a minute offset denticle. Mandibles 
usually with distinct longitudinal rugulose or striate sculpture, even in the smallest workers. Only rarely the 
smallest workers with mandibles virtually smooth. Eyes relatively small, the maximum diameter 0-14-0-20 
x HW and with 4-6 ommatidia in the longest row. In general eyes of smaller workers relatively somewhat 
larger in relation to head width than in larger workers, but not as conspicuously so as in oscaris. In larger 
workers CI is higher than in smaller workers, the heads becoming relatively broader with increased size. 
Antennal scapes relatively longer in small workers and shorter in larger individuals, as follows. 

When HW 0-40-0-45 then SI is 104-95; 

when HW 0-45-0-55 then SI is 97-85; 

when HW 0-55-0-65 then SI is 86-76; 

when HW 0-65-0-79 then SI is 78-70. 
Note that within the size intervals given the scapes are always relatively longer here than in oscaris (see 
below). Scapes when laid straight back from their insertions reaching the occipital margin in smallest 
workers but falling short of the margin in larger individuals. Alitrunk in profile with promesonotum convex 
and metanotal groove impressed. Petiole node in dorsal view globular to subglobular, not distinctly 
anteroposteriorly compressed. Occipital margin of head with 2-4 pairs of hairs forming a transverse row. 
Dorsum of head in front of this row but behind the frontal lobes with 1-4 pairs of hairs straddling the 
midline. Pubescence on head sparse and directed towards the midline. Promesonotal dorsum always with 
numerous elongate standing hairs; such hairs usually present on propodeum but may be lacking in small 
workers. Petiole, postpetiole and gaster with backward directed elongate hairs. Cephalic dorsum unsculp- 
tured except for scattered hair-pits. A band of fine transverse striolate sculpture present on the rim of the 
descending occipital surface of the head; this band of weak sculpture usually just visible in full-face view 
along the rim of the occipital margin. In the smallest workers this sculpture may be very faint or rarely even 
absent. Propodeal dorsum always finely transversely striolate to rugulose and usually with punctulate 
sculpture also present, at least in larger workers of any given series. The transverse sculpture is fainter in 
smaller than in larger workers but the overall intensity of the sculpture may vary between series. 
Promesonotum usually smooth and shining with scattered hair-pits, but peripheral faint sculpture may 
occur in large workers. Sides of pronotum smooth to vestigially striolate, the remainder of the sides of the 
alitrunk punctate to reticulate-punctate; the sculpture more intense and wider distributed in larger than in 
smaller workers. First gastral tergite smooth except for hair-pits. Head, alitrunk, petiole and postpetiole 
uniformly glossy yellow, varying in shade from light yellow to dull brownish yellow. Gaster always much 
darker, dark brown to blackish brown, usually with a conspicuous yellowish area mediobasally, the extent 
of which is very variable but is sometimes absent, leaving the gaster uniformly dark. 

A successful tramp-species, most probably of Indian origin, destructor is now widely distributed 
throughout the tropical zones of the world and is increasingly being spread into the temperate zones by 
commercial activity, where it is able to survive in constantly heated buildings. On describing the species 
Jerdon (1851) noted that these ants 'prefer animal to vegetable substances, destroying dead insects, bird 
skins, &c. but also feed greedily on sugar. They are common in all parts of India, and often prove very 
troublesome and destructive to the naturalist.' 

Krombein et al. (1979) give a good list of references dealing with the known biology of this species, and 



SOLENOPSIS GENUS-GROUP 325 

note that destructor has 'been reported to gnaw holes in fabrics, rubber goods, remove rubber insulation 
from electric or telephone wires, and damage polyethylene cable.' 

Two closely related species occur in sub-Saharan Africa, oscaris and mayri. The latter matches the 
description of destructor given above but is uniformly dark brown to blackish brown; see under mayri for 
further discussion. M. oscaris is uniformly coloured, unlike destructor, and has the petiole and postpetiole 
shaped differently in larger workers, compare Figs 39, 40. Apart from this the antennal scapes of destructor 
are relatively longer than those of oscaris in workers of comparable absolute dimensions, compare the 
tables given under their respective descriptions. 

Material examined 

Afrotropical region. South Africa: Natal, Durban (G. Arnold). 

Other regions. Cape Verde Is: Mindelo (M. L. LoboLima). Madagascar: Maevantanana (/. M. Wilson). 
Seychelle Is: Frigate I. (U. Muller). Andaman Is: North Bay (G. Rogers). Sri Lanka: Colombo (B. 
Laurence); Peradenya (A. Rutherford); Maha-Oyo Dist. (R. Winney); no loc. (coll. F. Smith). 
India: Calcutta (coll. F. Smith); Calicut (A. P. Rosy); NE. India, no loc. (S. P. Kurt). Nepal: Taplejung 
Dist. (R. L. Coe). Singapore: Sabang. Indonesia: Flores I., Maumere (W. L. Brown); Ternate I. (A. R. 
Wallace). Papua New Guinea: Saraga (J. W. Ismay); Cyclpos Mts, Sabron (L. E. Cheesman). Hawaii 
(/?. C. L. Perkins). Gilbert Is: Tarawa (E. S. Brown). Australia: Qld. (intercepted in quarantine). 
Oman (R. Whitcombe). Great Britain: London (R. A. Lever); London (R. Baggerley). Puerto Rico: 
Ensanda (M. R. Smith). Trinidad (no data). 

Monomorium emeryi Mayr 
Monomorium emeryi Mayr, 1895: 132. Syntype workers, Mozambique (H. Brauns)(NMV) [examined]. 

Worker. TL 2-5-3-4, HL 0-68-0-88, HW 0-62-0-80, CI 89-95, SL 0-52-0-67, SI 78-86, PW 0-36-0-50, 
AL 0-70-1-00 (20 measured). 

Mandibles conspicuously longitudinally rugulose to striate-rugulose, the basal tooth reduced to a minute 
denticle. Eyes relatively small, the maximum diameter 0T6-0-20 x HW and with 6-7 ommatidia in the 
longest row. Occipital margin in full-face view shallowly concave and somewhat indented medially. Head 
relatively broad and scapes short (CI and SI above). Promesonotum evenly domed-convex in profile, the 
metanotal groove shallowly impressed and the propodeal dorsum flat to very feebly convex. Propodeal 
dorsum on a much lower level than that of promesonotum. Petiole peduncle with an anteroventral low rim 
or flange. Usually this process runs back approximately to the level of the petiolar spiracle but may be 
reduced in some workers. Head without elongate standing hairs dorsally behind the level of the frontal 
lobes, but quite densely clothed with long decumbent to appressed pubescence which is directed towards 
the dorsal midline. Similar long pubescence present on all surfaces of dorsal alitrunk but also with much 
longer conspicuous standing hairs present both on promesonotum and propodeum. Long back-curved 
hairs numerous on petiole, postpetiole and first gastral tergite and sternite; all these segments also with 
elongate but relatively sparse pubescence which is decumbent to appressed. Entire dorsum of head densely 
longitudinally costulate to rugulose, the sculpture usually quite regular and always with fairly conspicuous 
punctures visible between the longitudinal components. On sides of head the sculpture tends to fade out or 
become much less dense below and behind the eyes. Dorsal alitrunk reticulate-punctate, this sculpture 
overlaid by fine rugular or costulate sculpture which may vary in density and direction on the promesono- 
tum even in members of a single nest-series, but is always transverse on the propodeal dorsum. Sides of 
alitrunk with rugular or costulate sciilpture usually also present on the pronotum, metapleuron and 
propodeum. Punctate component sometimes reduced on sides of pronotum so that only faint longitudinal 
rugulae remain. Rugulae sometimes absent from metapleuron and propodeal sides, leaving the area 
reticulate-punctate. Petiole and postpetiole generally smooth dorsally but with lateral sculptural vestiges 
remaining. First gastral tergite unsculptured except for hair-pits. Colour light to dark brown, usually 
uniform. 

This distinctive heavily sculptured species shows very little size variation in any given series and the 
marked allometric variation characteristic of oscaris does not occur. The form and density of the sculpture 
immediately isolates emeryi from all other members of the destructor-group. The male of emeryi, described 
by Arnold (1916), is very similar to that of destructor and oscaris (see p. 323). 

Material examined 
Malawi: Salima Bay (G. Arnold). Zimbabwe: Victoria Falls (G. Arnold); Redbank (G. Arnold); 



326 B. BOLTON 

Cawston Farm (G. Arnold). Mozambique: no loc. (H. Brauns). Botswana: Okavango Delta, Smiti (A. 
Russel-Smith); Serowe (P. Forchhammer) . 

Monomorium epinotale Santschi 

Monomorium (Parholcomyrmex) epinotale Santschi, 1923: 281. Syntype workers, Zaire: Luluaborg, 
16.1.1912 (R. P. Callewaert) (MNB; MRAC) [examined]. 

M. epinotale, presently known only from the syntypic series, is exceptionally close to oscaris, differing 
only in colour. When more material is known epinotale will most probably fall into the synonymy of oscaris. 
For the present epinotale answers the description of oscaris in all respects but is coloured as follows. 

Head and gaster yellow. Alitrunk chestnut-brown to dark brown. Petiole and postpetiole usually the 
same colour as the alitrunk but may be slightly lighter; the petiole and postpetiole are, however, always 
much darker in colour than the gaster. 

Material examined 
Zaire: Luluaborg (R. P. Callewaert). 

Monomorium mayri Forel stat. n. 

(Fig. 34) 

Monomorium gracillimum var. mayri Forel, 1902a: 209. Syntype workers, India (MHN) [examined]. 
Monomorium destructor r. gracillimum var. karawajewi Forel, 1913d: 437. Syntype workers, Sudan: 

Khartoum (Karavaiev), and Israel: Rehovot, near Tel Aviv-Yafo (Jaffa) (Aharoni) (MHN) 

[examined]. [Unavailable name.] 

Answering the description of destructor in all respects except colour, mayri being uniformly dark brown, 
sometimes with a paler patch at the base of the first gastral tergite. 

I have decided to retain mayri as a valid species, separate from destructor, for the time being. The colour 
character is admittedly feeble but appears to be consistent, and mayri does not show the tramping ability so 
strongly developed in destructor. Compared to the range of destructor (widespread in India and nearby 
states, and patchily introduced in many other parts of the tropics by man), the range of mayri covers a very 
wide continuous broad band of territory, stretching from east to west. Like destructor I suspect the Indian 
subcontinent of being the place of origin of mayri, and westward from there its range extends across the 
Middle and Near East and through the Sahelian zone of sub-Saharan Africa. Eastwards from India mayri is 
recorded from Thailand and Malaysia. 

Material examined 

Afrotropical region. Mali: Tessalit (P. Room). Niger: Italemen (J. Newby). Sudan: Khartoum (R. 
Cottam); Khartoum (Karavaiev). 

Other regions. Egypt: Gara (J. Omer-Cooper) . Oman: Khabura Farm (R. P. Whitcombe); Dhofar, 
Wadi Sayq. Israel: Rehovot (Aharoni). Syria: no loc. (ex coll. Saunders). Iraq: Baghdad (Y. R. Rao); 
Baghdad (P. A. Buxton); Fatah (H. D. Peile). Saudi Arabia: Jiddah (A. C. Trott); Jiddah (G. L. Bates); 
Mukalla (H. SU. B. Philby). South Yemen: Al Huseini (H. Scott & E. B. Britton). India: Tamil Nadu, 
Mudumalai (/. S. Noyes); Madras. Sri Lanka: Peradenya (Green). Thailand: Chang Khian, Chiang Mai 
(D. Jackson); Bangkok (H. Hillman). West Malaysia: Sg. Patani (G. H. Lowe). 

Monomorium oscaris Forel 
(Fig. 40) 

Monomorium oscaris Forel, 1894a: 86. Holotype worker, Ethiopia: 'Sudabessinien' (Ilg) (MHN) 

[examined]. 
Monomorium dispar Emery, 18956: 24. Syntype workers, South Africa: Transvaal, Makapan (E. Simon) 

(MCSN) [examined]. Syn. n. 
Rhoptromyrmex soiled Forel, 1910a: 430. Holotype female, Senegal: Bissao (Soller) (MHN) [examined]. 

[solleri transferred to Monomorium by Ettershank & Brown, 1964: 18.] Syn. n. 
Monomorium destructor subsp. kalahariense Forel, 1910c: 18. Syntype workers, Botswana: Kalahari, 

Kooa-Sekgoma (L. Schultze) (MHN) [examined] . Syn. n. 



SOLENOPSIS GENUS-GROUP 327 

Monomorium destructor subsp. kalahariense var. despecta Forel, 191CW: 252. Syntype workers, Ethiopia: 

Ghinda (K. Escherich) (MHN) [examined]. [Unavailable name.] 
Monomorium amblyops r. bulawayense Forel, 1914: 247. Syntype workers, Zimbabwe: Bulawayo, 

Hillside, 8.H.1914, no. 270 (A. M. Macgregor) (MHN) [examined]. [Junior primary homonym of M. 

exiguum var. bulawayensis Forel, 1913c: 217.] 
Monomorium amblyops r. prossae Forel, 1916: 418. [Replacement name for M. amblyops r. bulawayense 

Forel, 1914: 247.] Syn. n. 

Worker. TL 1-6-3-8, HL 0-46-0-94, HW 0-36-0-84, CI 76-90, SL 0-34-0-54, SI 63-94, PW 0-24-0-52, 
AL 0-48-1 -00 (30 measured) . 

Workers showing marked size variation in any given series, and displaying monophasic allometric 
variation. Mandibles with 3 strong teeth, the fourth (basal) tooth reduced to a minute offset denticle or 
even lost in the smallest workers. Mandibles frequently showing longitudinal rugular sculpture but often 
smooth. Usually larger workers have the mandibles more strongly sculptured than smaller individuals, but 
this is by no means universal. Eyes relatively small, the maximum diameter 0-13-0-19 x HW and with 3-6 
ommatidia in the longest row. Eyes of larger workers have more ommatidia than those of smaller workers 
but are smaller in relation to the size of the head. In small workers, with HW < 0-60, the eyes are 
approximately 0-15-0-19 x HW, whilst in workers with HW > 0.60 the eyes range 0-13-0-16 x HW. In 
large workers CI is higher than in small, the heads being relatively broader. Antennal scapes relatively 
longer in small workers and shorter in large workers, as follows. 

When HW 0-35-0-45 then SI is 94-84; 

when HW 0-45-0-55 then SI is 84-79; 

when HW 0-55-0-65 then SI is 76-69; 

when HW 0-65-0-75 then SI is 74-64; 

when HW 0-75-0-85 then SI is 65-63. 
When laid straight back from their insertions the scapes almost reach the occipital margin in smallest 
workers but fall far short of the margin in the largest individuals. With the head in full-face view the sides 
shallowly convex and the occipital margin shallowly concave in large workers; in small workers the sides 
and occipital margin tend to become straighter. Alitrunk in profile with promesonotum convex, the 
metanotal groove impressed. In dorsal view the petiole node conspicuously anteroposteriorly compressed 
in large workers, distinctly much broader than long. Postpetiole in dorsal view broader than long. Occipital 
margin of head with 2-4 or more pairs of standing hairs forming a transverse row. Dorsum of head in front 
of this row but behind the frontal lobes with 1-4 pairs of standing hairs straddling the midline. Pubescence 
on head sparse, directed towards the midline. Promesonotal dorsum always with numerous standing hairs; 
such hairs also present on propodeum in large to medium workers but sometimes absent in small 
individuals. Petiole, postpetiole and gaster each with numerous elongate backward directed hairs. 
Sculpture usually absent from cephalic dorsum, the surface glassy smooth between scattered hair-pits. 
Medium to large workers with a band of fine transverse striolate sculpture on the rim of the descending 
occipital surface of the head; this band of weak sculpture usually just visible in full-face view along the rim 
of the occipital margin. In smaller workers this transverse occipital sculpture is much reduced or absent. 
Largest workers in some West African samples with the cephalic dorsum showing very fine vestiges of 
sculpture between the hair-pits. Propodeal dorsum always finely transversely striolate to transversely 
rugulose; fainter in smaller workers than in larger. Promesonotal dorsum usually smooth with scattered 
hair-pits, but faint scratch-like or patchy striolate sculpture occurs in the large workers of some samples; a 
small patch of superficial punctulation may occur at the pronotal-mesonotal junction. Sides of pronotum 
smooth to vestigially striolate, the remainder of the lateral alitrunk punctuate to reticulate-punctate. First 
gastral tergite smooth except for hair-pits. Colour yellow to light brownish yellow, glossy. 

A widely distributed and versatile species which ranges over most of the Afrotropical region outside the 
rainforest zone or within that zone in cleared areas . Arnold (1916) records that in Zimbabwe it nests under 
stones along with a small species of termite, but that the galleries of the two are not interconnected. In 
Nigeria I have found oscaris in termitaria and nesting in the earth, but on one occasion a nest was found in 
an old and rotting cocoa pod which was still attached to the tree, some distance above the ground. 

The closest relative of oscaris appears to be the pantropical tramp-species destructor, but the two are 
separable by the shape of the petiole node in dorsal view, especially in larger workers (Figs 39, 40). In 
destructor the node is globular to subglobular but in oscaris it is strongly anteroposteriorly compressed and 
markedly transverse. Also, at any given worker size, the scapes tend to be longer in destructor than in 
oscaris: compare the tables under their respective descriptions. 

It is possible that the names ominosa and atomaria, both described from East Africa and subsequently 



328 B. BOLTON 

synonymized with destructor, may represent early records of oscaris. However, as the original descriptions 
are so poor, and as the specimens involved seemingly have long since disappeared, there is no way of 
proving this; in consequence they are left undisturbed as junior synonyms of destructor. The West African 
population of oscaris may eventually prove to be separable at species-level from the eastern and southern 
population. Females of the western population, which correspond to the name solleri in the above 
synonymy, are lighter in colour and tend to have the mesoscutum relatively broad. The largest workers 
from this area tend to show faint cephalic sculpture. The amassing of more material will be necessary 
before a meaningful analysis of these features can be undertaken. 

Material examined 

Ghana: Legon (D. Leston); Legon (G. Benson); Navrongo (P. Room) ; Dawhenya (C. A. Collingwood). 
Nigeria: Gambari (B. Bolton); Gambari (B. Taylor); Mokwa (C. Longhurst); Ibadan (R. Ouhang). 
Ethiopia: Ghinda (K. Escherich). Uganda: Kawanda (R. M. C. Williams). Zaire: Yakuluku (H. O. Lang). 
Tanzania: Shinyanga (O. W. Richards); Tanga, Pituzika (M. J. Way). Zimbabwe: Bulawayo (A. M. 
Macgregor); Bulawayo (G. Arnold); nr Harare (W. H. S.). Botswana: Kalahari, Kooa-Sekgoma (L. 
Schultze). South Africa: Transvaal, Makapan (E. Simon). 

Monomorium robustior Forel stat. n. 

(Figs 35, 41) 

Monomorium gracillimum r. robustior Forel, 1892a: 352. Syntype workers, Somalia (C. Keller) (MHN) 

[examined]. 
[Monomorium gracillimum r. robustius Forel, 1894b: 228. Misspelling of robustior.] 

Worker. TL 2-5-3-4, HL 0-68-0-84, HW 0-62-0-78, CI 90-97, SL 0-52-0-66, SI 82-88, PW 0-36-0-46, 
AL 0-70-0-92 (20 measured). 

Mandibles strongly longitudinally rugulose, the basal (fourth) tooth reduced to a minute denticle. 
Maximum diameter of eye 0-18-0-20 x HW and with 6-8 ommatidia in the longest row. Sides of head 
feebly convex in full-face view, the occipital margin concave or indented medially. Promesonotum domed 
in profile, the metanotal groove shallowly impressed; propodeal dorsum on a lower level than that of the 
promesonotum. Cephalic dorsum usually without standing hairs behind the level of the frontal lobes, but in 
some larger workers a single pair is present straddling the midline close to the occipital margin. Even more 
rarely a second pair may occur mid-dorsally between the level of the posterior margins of the eyes and the 
occipital margin. Entire dorsum of head with long fine pubescence which is decumbent to appressed and is 
directed toward the midline. Dorsal alitrunk also with similar appressed pubescence but all surfaces also 
with long standing hairs present. Petiole, postpetiole, first gastral tergite and first sternite with numerous 
long back-curved hairs and with sparse appressed pubescence. Dorsum and sides of head and promesono- 
tum unsculptured, smooth except for small scattered hair-pits. Remainder of sides of alitrunk reticulate- 
punctate, the metapleuron and propodeal sides usually overlaid by rugular sculpture. Propodeal dorsum 
finely transversely rugulose, usually with punctate interspaces, the latter variable in intensity. Petiole 
and postpetiole either with sculptural vestiges laterally or entirely smooth; first gastral tergite un- 
sculptured except for scattered hair-pits. Colour medium to dark brown on the head and alitrunk, 
sometimes with a reddish tint. Gaster dark brown to blackish brown, usually darker in shade than the 
head and alitrunk. 

M. robustior, an East African and Malagasy species, was originally described as a 'race' of gracillimum 
(the latter now a synonym of destructor) by Forel (1892a). The colour and habitus of robustior approaches 
that of mayri most closely and the species should not be associated with destructor. 

M. mayri and robustior are superficially similar but samples of the latter do not show the extreme 
variations of worker size seen in the former. Apart from this the occipital area of the head is smooth in 
robustior but has faint transverse rugulose sculpture in mayri (and also in destructor). The transverse 
rugular sculpture on the propodeal dorsum tends to be fine and dense in mayri, coarse and more broadly 
spaced in robustior. The occipital margin of the head has a transverse row of 4-6 standing hairs in mayri 
where at most 1 pair, and usually none, occurs in robustior. The eyes of robustior average larger than those 
of mayri or destructor (see measurements under the latter name), and the hairs on the first gastral tergite 
are much longer and more strongly curved in robustior than in either destructor or mayri; compare Figs 34, 
35. 



SOLENOPSIS GENUS-GROUP 329 

Material examined 

Somalia: no loc. (C. Keller). Kenya: Amboseli (E. S. Brown); Kajiado (G. Nyamasyo); Kora (C. West); 
Kora (N. M. Collins & M. Ritchie). Madagascar: Amboasary (J. M. Wilson); Bereboka, nr Morondava 
(/. S. Noyes & M. C. Day); Bereboka (W. L. Brown); Betroka (E. S. Ross & R. E. Leech). 

The salomonis-group 

(Figs 22, 24, 25, 27-30, 36-38, 42-56, 60) 

Worker. Monomorphic, usually with some size variation in any series but without allometric variation. 
Palp formula 2,2 (albopilosum, areniphilum , afrum, bicolor, damarense , drapenum, indicum, junodi, 
minor, niloticum, marshi, pharaonis, rufulum, salomonis, subopacum, sutu, viator, westi), reduced to PF 
1,2 in some minute species (osiridis, rabirium, by in situ count) and in the socially parasitic noualhieri. 
Mandibles sculptured except in a few, usually very small, species. Masticatory margins of mandibles with 4 
teeth which decrease in size from apex to base, the basal tooth not reduced to a minute denticle except in 
rufulum. Trulleum small to obliterated, when present either open or closed. Median portion of clypeus 
raised, projecting forward anteriorly, bicarinate to rounded along lateral margins of raised portion. 
Median portion of clypeus posteriorly broader than either of the frontal lobes where it passes between 
them. Anterior clypeal margin without a widely separated pair of teeth although anterior ends of clypeal 
carinae may be denticulate or sharply pointed in some species. Cephalic dorsum usually sculptured (not so 
in only a very few species), the sculpture ranging from dense blanketing reticulate-punctuation to faint 
superficial reticular patterning. Eyes distinct and moderate to large in size (0-19-0-40 x HW), generally 
with 6 or more ommatidia in the longest row; eyes situated at or very close to the midlengths of the sides of 
the head. Eyes circular to roughly oval, never reniform nor extended anteroventrally into a lobe. Head 
always longer than broad (CI < 90) and scapes usually relatively long (SI > 90, with very few exceptions). 
Antennae with 12 segments, terminating in a club of 3 segments. Metanotal groove moderately impressed 
to absent. Metanotal cross-ribs inconspicuous to absent; when present often short and masked by other 
sculpture. Propodeal spiracle circular to subcircular. Propodeum rounded to angular between dorsum and 
declivity, rarely the angle weakly dentate. Propodeal dorsum usually sculptured but never transversely 
striate; only very rarely the dorsum smooth. Petiolar spiracle at the node or immediately in front of the 
anterior face of the node. Body pilosity very variable in distribution and density, but with a marked 
tendency to reduce the pilosity, especially on the head and alitrunk. Alitrunk, petiole and postpetiole 
usually conspicuously sculptured. First gastral tergite frequently shagreenate or otherwise finely sculp- 
tured. (Workers examined: all included in this revision plus the following extralimital species. M. albeillei, 
algiricum, buxtoni, dichroum, hesperium, indicum, longi, medinae, niloticum, pallidum, salomonis, 
schurri, subnitidum, venustum, wroughtoni, plus 12 indeterminate species.) 

Female. Characters generally as worker but female much larger; only slightly larger than the conspecific 
male. Eyes usually larger than in worker, at or only slightly behind midlength of sides. Ocelli present 
except in extreme ergatoids where the eyes are also reduced to worker-size. Antennae with 12 segments, 
the apical club of 3 segments or rarely of 4 (effractor, santschii). In afrum the club is feebly 4-segmented as 
the eighth funicular segment is moderately enlarged. HW slightly to very distinctly greater than maximum 
width of mesoscutum. In very few females the two of about equal width but in ergatoids the head 
conspicuously wider than the mesoscutum. Alitrunk usually winged in virgins and with a full complement 
of flight sclerites, but several apterous or ergatoid forms are known which fail to develop wings and show a 
serial reduction of flight sclerites. (Apterous to ergatoid females are known in bicolor, albopilosum, 
rufulum, venustum, opacior, medinae, minor, hesperium, dichroum, advena, algiricum, damarense , biroi, 
grassei, libanicum, syriacum, of which the last seven are extreme ergatoids.) A few species are known 
which may produce both apterous and alate females. Mesoscutum very prominent and bulging anteriorly in 
some known or suspected social parasites (afrum , effractor , santschii), strongly overhanging the pronotum. 
Parapsidal grooves varying from conspicuous to absent. Axillae usually triangular in alate forms, separated 
mid-dorsally by a small gap. Axillae fused to mesoscutum in many apterous and ergatoid forms. Petiole and 
postpetiole varying from subconical and nodiform respectively to both strongly anteroposteriorly 
compressed. Forewings with cross-vein m-cu absent. Head and alitrunk conspicuously sculptured; first 
gastral tergite usually also sculptured, even if only faintly so. (Females examined: advena, afrum, 
albopilosum, algiricum, areniphilum, bicolor, damarense, delagoense, dichroum, dictator, effractor, 
herero, hesperium, indicum, junodi, medinae, minor, ocellatum, opacior , pharaonis , rufulum, salomonis, 
santschii, subdentatum, subnitidum, subopacum, venustum.) 



330 B. BOLTON 

Male. About same size as or slightly smaller than conspecific female, much larger than worker. Palp 
formula 2,2 in all examined (perhaps reducing to PF 1,2 in minute species). Mandibles strongly developed 
and 4-dentate except in pharaonis-comp\ex where they are relatively small and have 2-3 teeth. Scape 
cylindrical or subcylindrical, varying in length but usually quite short, about equal in length to funiculus 
segment 2, or slightly longer. First funicular segment not globular, remaining funicular segments not 
whip-like, but tapering apically in excelsior. Head capsule wider behind eyes than in front, maximum width 
of head about equal to maximum width of mesoscutum. Eyes large and approximately at midlength of 
sides; always a distinct space between the eye and the mandible, the eye not touching the clypeus. Ocelli 
large, not born on a turret and not breaking the outline of the occipital margin. Mesoscutum overhanging 
pronotum anteriorly, strongly produced and bulging forward in socially parasitic species (effractor, 
santschii). Notauli absent but mesoscutum with a narrow V-shaped anteromedian area which is only 
weakly sculptured or is smooth. Parapsidal grooves present to absent. Axillae small, triangular in dorsal 
view and separated dorsally by a groove; axillae usually fused to scutellum, sometimes also fused to 
mesoscutum. Propodeal spiracle far forward, in front of midlength of sclerite. Wings present in all known 
males, with cross-vein m-cu absent. Head and alitrunk sculptured, usually densely so. Predominant 
sculpture is reticulate-punctation throughout. First gastral tergite usually finely sculptured. Genitalia large 
to massive, partially retractile and bizzarely modified in some species. (Males examined: afrum, albopilo- 
sum, bicolor, delagoense, effractor, excelsior, indicum, junodi, medinae, minor, pharaonis, rufulum, 
santschii, subopacum, ocellatum, viator.) 

One of the largest species-groups of Monomorium, the Salomon w-group is fairly uniform and contains 48 
currently recognized species in the Afrotropical region. Many more species are distributed throughout the 
width of Africa north of the Sahara, the Middle East and the eastern Palaerctic and Oriental regions. A few 
species occur north of the Mediterranean or on islands in that sea, and several species are accomplished 
tramps, being transported widely by commercial activity. The definition given above covers the entire 
group, not just the Afrotropical fauna. 

Unlike most other groups within Monomorium, salomonis-group members are usually distinguished by 
their conspicuous fine sculpture and marked tendency to reduce the pilosity of the dorsal head and body. 
Forms with much-reduced sculpture are relatively rare in the group but these species, which may come 
superficially to resemble members of the monomorium-group, usually also exhibit a marked lack of dorsal 
pilosity on the head and body. In smooth species of the monomorium-group dorsal pilosity is generally 
strongly developed. In general even species of the Salomon w-group which have lost most or all sculpture 
dorsally tend to retain it laterally on the alitrunk and everywhere on the propodeum. 

This species-group is based broadly on the old concept of a subgenus Xeromyrmex, now synonymized, 
though with many inclusions and exclusions from the form of the group as envisaged by Emery (1922) and 
Wheeler (1922). Xeromyrmex was extremely feebly defined from its inception, and even as early as 1917 
Forel considered the subgenus to be insufficiently defined. The Emery-Wheeler classification of 1922 did 
nothing to improve the stability of the taxon and their joint inclusion of forms not really belonging here, 
coupled with the exclusion of others for various reasons, only served to confirm that the subgenus was 
undefinable except in terms of species not fitting anywhere else, grouped loosely on habitus or variable 
character states. Both Emery and Wheeler relied to a great extent on the relative lengths of antennal club 
segments to differentiate their subgenera. Arnold (1944) carried out some careful measurements and 
demolished the assumed usefulness of this character. Incidentally he also demolished a large part of the 
subgeneric structure of Monomorium, but proposed no new system to take it place. It was left to 
Ettershank (1966) formally to abandon the useless subgenera, clearing the way for the delineation of more 
meaningful associations of species within the genus. 

Another source of confusion within this group, this time at species-level, was the strange habit of early 
workers of describing any new forms of which they were unsure as infraspecific or infrasubspecific variants 
oisalomonis itself, even when the form under description bore only superficial resemblance to that species. 
The habit later spread to bicolor, as discussed below. Of the region's 48 currently valid species two were 
first described as infraspecific forms of subopacum, 4 of bicolor, and fully 14 as infraspecific forms of 
salomonis. 

Members of the salomonis-group are characteristically inhabitants of dry ground and well-drained soils, 
ranging from Mediterranean climate through savannah and semi-desert to hard desert conditions, and 
frequently nesting in exposed places where the soil receives direct insolation. It has been postulated 
(Bolton, 19866) that this may in part be responsible for the frequent development of apterous and ergatoid 
females within the group. In the few species which have been observed salomonis-group members are 
scavengers and predators of small arthropods. 

The Afrotropical species are divided into 8 complexes here, mostly for convenience and to point out 



SOLENOPSIS GENUS-GROUP 331 

obvious resemblances among various members of the mass of species. Extralimital species-complexes are 
not discussed and for the greater part remain uninvestigated, though all available material has been 
examined during this study. It is not claimed that the species-complexes mentioned below reflect any 
particular phylogenetic significance, too little is known of most species to warrent any such assumption; 
the salomonis-group as a whole does, however, appear to constitute a holophyletic group within 
Monomorium. 



Afrotropical species-complexes of the salomonis-group (based on workers) 

Note that distribution and density of standing pilosity is important in the species-level taxonomy of this 
group. Old or abraded specimens should be treated with circumspection. The complexes are based on the 
worker caste as relatively few females and males are known. 

The £>/co/or-complex contains six species characterized by their distinctive colouring and sharply defined 
dense sculpture. The head and alitrunk are orange-yellow to red and the gaster dark brown to black, the 
latter often with steely or bluish reflections. The two colour zones contrast strongly. All surfaces of the 
head and alitrunk are blanketed by fine and very dense reticulate-punctate sculpture in which 
the individual punctures are small but very sharply defined. The sculpture is not reduced or effaced 
anywhere and the cephalic punctures do not have a smeared or run-together appearance. Standing hairs 
are always present on the first gastral tergite in front of the apical transverse row. Such hairs are usually 
absent from the dorsal alitrunk but are numerous in hirsutum and one pronotal pair may occur in some 
samples of rufulum. 

Members of the fe/co/or-complex are closest related to those of the opacum-comp\ex, with which they 
share the same pilosity and form of sculpture. In the opacum-complex, however, the body is uniformly 
brown or black, or dark brown with a darker gaster; the contrasting colours of the fr/co/or-complex are not 
developed. Ignoring the difference in colour these two complexes could easily be combined, so closely are 
they related. 

Of the six species in the bicolor-comp\ex four are of relatively limited distribution. M. hirsutum is known 
only from Ethiopia, westi from Kenya, personatum and dictator from Angola. M. bicolor is very widely 
distributed in the northern, western, central and eastern portions of the Afrotropical region, and also 
occurs in the southern Palaearctic, where it is replaced in part by a sibling-species, nitidiventre, around the 
eastern end of the Mediterranean. The final species, rufulum, is widely distributed in southern Africa and 
apparently replaces bicolor in Angola, Namibia, Botswana and Zimbabwe (where it was recorded as 
nitidiventre by Arnold (1916)). All appear to be species of savannah, arid zones, or forest clearings where 
there is well-drained soil and direct insolation. 

M. bicolor was, prior to this study, one of the overworked 'form-species' previously much used in the 
salomonis-group. Any red and black Monomorium of the salomonis-group was described and appended to 
bicolor, forming a welter of infraspecific forms which quickly swamped the nomenclature and rendered 
accurate identification impossible. The full panoply of names formerly attached to bicolor, in the 
Afrotropical region, included the varieties coerulescens, rufibasis, uelensis, aequatoriale , tropicale; the 
subspecies (or stirps) hirsutum, dictator, dakarense, personatum, ebangaense; and the infrasubspecific 
names impuriceps, bimaculatum and bimaculatoides . Of these names hirsutum, dictator, personatum, and 
dakarense are now regarded as valid species in the Salomon w-group (the first three in the 6/co/or-complex); 
ebangaense is a valid species but belongs to the setigerum-group . The remainder are synonyms of the 
various bicolo r-complex species. 

Males are known for bicolor and rufulum, females for these two species and dictator; sexual forms 
otherwise unknown. 

The opacum-comp\ex. A small complex of 6 species characterized by their uniformly dull brown colour 
and sharply defined dense reticulate-punctate sculpture which blankets the head and alitrunk. This 
complex consists of a central core of four species (junodi, micropacum, opacum, subdentatum) and two 
peripheral species included for convenience (afrum, albopilosum). Of these peripheral species afrum 
appears to be related to opacum but is noticeably more specialized, having lost its gastral pilosity and 
independently acquired its diagnostic modification of sharp posteroventral occipital corners. M. albopilo- 
sum, though sharing the characters of colour and sculpture with the rest of the complex, is abundantly 
hairy. The core-species of the complex are closely related to the members of the i»/ro/or-complex on one 
hand (see above), and to the subopacum-comp\ex on the other. The latter complex, however, has very 
reduced cephalic sculpture. 

M. afrum is widely distributed through the drier zones of the entire continent , but does not seem to occur 
in deserts. The remaining species are apparently restricted to the southern and eastern parts of the 



332 B. BOLTON 

Afrotropical region. Males and females are known for afrum, albopilosum, and junodi; sexual forms of the 
rest remain unknown. 

The subopacum-complex, which contains 8 Afrotropical species, shows cephalic sculpture which is much 
more reduced than in either of the complexes so far discussed. Instead of the head being uniformly sharply 
reticulate-punctate the sculpture here is reduced to reticulate-granular, shagreenate-punctate, or to a fine 
superficial reticular patterning which appears inlaid in the surface and does not roughen the surface. In 
general the alitrunk is more strongly sculptured than the head or both areas show distinct sculpture. The 
alitrunk (Figs 48, 49, 54) does not show the characteristic outline of the areniphilum-complex (Fig. 46). 

Within the complex blanketing fine cephalic sculpture is shown by ocellatum and subopacum, whilst 
herero shows the same sculpture in reduced form, appearing roughly reticulate. The retaining species 
{delagoense , drapenum, kitectum, ophthalmicum, willowmorense) have cephalic sculpture reduced to fine 
superficial reticulation or reticular patterning only, as is also seen in the tchelichofi-complex; in this latter 
complex, however, the alitrunk also has very reduced sculpture. All species have one or more pairs of 
standing hairs present on the first gastral tergite in front of the apical transverse row. 

This complex is intermediate in sculptural reduction between the opacum-complex, where sculpture is 
strong, and the tchelichofi-complex in which sculpture is very reduced indeed. All members of the 
subopacum-complex are restricted to southern Africa except for ophthalmicum from Ethiopia and 
subopacum itself. The latter is very widely distributed but appears originally to have been a circum- 
Mediterranean species which has subsequently been spread by commercial activity. 

Males and females are known for subopacum and delagoense (described briefly by Forel, 1910/)); the 
females of ocellatum and herero are known but both sexual forms of all the rest await discovery. 

The tchelichofi-comp\ex. The five species of this complex are characterized by the reduction of cephalic 
sculpture to a fine superficial reticular patterning which does not roughen the surface but rather appears 
inlaid into the surface. The alitrunk sculpture is also much reduced and in general the promesonotum is not 
more strongly sculptured than the head. Hairs are present on the first gastral tergite in front of the apical 
transverse row. 

Known from four South African and one Ethiopian species the members of this complex form an 
apparently close-knit unit within the Salomon w-group because of their very reduced sculpture, though 
whether this constitutes an apomorphy cannot presently be assessed. Superficially all the species seem 
quite smooth and glossy, but closer examination reveals the presence of extremely fine superficial reticular 
patterning, which appears inlaid in the cuticle. Loss of this fine patterning would leave the surface entirely 
featureless. 

The tchelichofi-complex seems to form the final stage in a sequence of sculptural reduction which begins 
in the universal dense reticulate-punctation seen in the opacum-complex. This sculpture is reduced in the 
subopacum-complex either evenly over the entire body or partially, on the head, leaving the alitrunk 
dorsum more strongly sculptured than the cephalic dorsum. In tchelichofi and its allies the sculpture is 
reduced all over the head and promesonotum, so that the latter is no more strongly sculptured than the 
former. The only sexual form known in this complex is the male of excelsior. 

The areniphilum-comp\ex. The single Afrotropical species currently occupying this complex, areniphi- 
lum, is recognized by its cephalic sculpture, which is finely reticulate to reticulate-shagreenate but usually 
overlaid by very fine dense scratch-like longitudinal striation, by its large eyes, and by its characteristically 
shaped alitrunk outline (Fig. 46). The antennal scapes in areniphilum are of moderate length (SI 98-104) 
and the first gastral tergite has at most a single pair of standing hairs in front of the apical transverse row. 

M. areniphilum is circum-Saharan in distribution and several related forms occur in North Africa. The 
taxonomy of the North African and Middle Eastern forms related to areniphilum is very confused and 
much in need of study. 

The viator-complex. A complex of four Namib Desert species which are isolated within the salomonis- 
group by a combination of characters including reduced cephalic sculpture, which is superficially reticulate 
to reticulate-granular; never with sharply defined reticulate-punctate sculpture. The eyes are moderate to 
very large (0.26-0.40 X HW), and the scapes are long to very long (SI 111-130). Standing hairs are always 
numerous and fairly evenly distributed on the first gastral tergite in front of the apical transverse row. 

Cephalic sculpture in this complex covers the same range of variation as is seen in the subopacum- 
complex, but the scapes there are shorter and the outline shape of the head tends to be different. In viator 
and allies the head in full-face view has the sides in front of the eyes approximately parallel to weakly 
divergent anteriorly, and the sides behind the eyes convergent posteriorly (Figs 52, 53). In the subopacum- 
complex the sides tend to be evenly shallowly convex, broadest across the midlength and converging both 
in front of and behind the eyes. Two of the species noted by Marsh (1984) in his pitfall survey of Namib 
Desert ants are included here. Marsh's Monomorium sp. A = viator, and his sp. B = vatranum. The other 
two species included in the complex are mantazenum and marshi, also discovered in the Namib by Marsh. 



SOLENOPSIS GENUS-GROUP 333 

The male of viator is known, all other sexuals are unknown for the members of this complex. 

The mediocre-complex. A convenience complex to hold five southern African and one Kenyan species 
which lack pilosity on the alitrunk and on the first gastral tergite in front of the apical transverse row, and 
which may even lack the apical row itself. All show very reduced sculpture everywhere. In all species 
cephalic sculpture is represented by faint to vestigial superficial reticular patterning, similar to but fainter 
than that seen in the much larger species of the tchelichofi-complex. 

The four small species esharre, osiridis, rabirium, and zulu have eyes which are in front of the midlength 
of the sides of the head, a condition very rare in the salomonis-group as defined here but characteristic of 
the setuliferum-group . In esharre the eyes remain close to the midlength, but in the other three the forward 
shift is obvious. It seems most probable that these species have acquired this character independently of the 
setuliferum-group as otherwise they do not conform to the diagnosis of that group. However, as the 
setuliferum-group itself is essentially a catch-all group, holding complexes of species which do not easily fit 
elsewhere, judgement on the correct placement of esharre and its allies must be deferred, pending further 
investigation. 

In situ count of the palp formula shows that osiridis and rabirium have a reduced PF 1 ,2, rather than the 
PF 2,2 usual in the salomonis-group. Whether this applies to all species currently placed in the mediocre- 
complex remains to be seen as shortage of material and lack of suitably exposed mouthparts in the few 
specimens available precludes further investigation. 

Because of their reduced sculpture and forward shifted eyes osiridis, zulu and rabirium may be suspected 
of being specialized monomorium-group members which have acquired sculpture, rather than salomonis- 
group members which have shifted eyes and reduced sculpture. I regard the three as specialized members 
of the salomonis-group, not only because they retain vestiges of the characteristic salomonis-group 
sculpture but also because they have grossly reduced pilosity, a trait not seen in the monomorium-group, 
and because they grade back into the mass of the salomonis-group, through the more normal members of 
this complex, namely esharre, mediocre and nirvanum. Sexual forms of all mediocre-complex members 
remain unknown. 

The australe-complex. A complex of 12 small to minute species (HW 0-42-0-57) in the salomonis-group 
in which the head is opaque, shagreenate-granular to punctulate-shagreenate, and frequently with the 
mid-dorsal strip of the head showing extremely fine longitudinal scratch-like striolae. The sculpture of the 
whole head usually has a smeared or silky appearance under low magnification as it is so fine. This form of 
cephalic sculpture is strongest developed in carbo, darkarense , minor, damarense , parvinode , opacior and 
sutu, tending to be somewhat fainter in disertum, and reduced in australe, anceps and termitarium. The first 
gastral tergite retains hairs in front of the apical transverse row (except in some samples of damarense), 
which may be evenly dispersed on the sclerite or restricted to 2-3 pairs on the basal half. The dorsal 
alitrunk lacks standing hairs in all species. Eyes are of moderate size (0-24-0-31 x HW except in sutu where 
they are large (0-35-0-38 x HW), and frequently are slightly in front of the midlength of the sides. 

Of the 12 included species 7 occur only in the countries of southern Africa. Two, carbo and parvinode , 
are only known from Ethiopia and Sudan, one (sutu) is Kenyan, and dakarense is known from a single 
sample from Senegal. 

Also included in this complex is senegalense, a nomen dubium. No type-material of this enigmatic form 
appears to have survived, but from Roger's (1862) brief description the species seems to fall here. It is just 
possible that senegalense may be a senior synonym of dakarense. Male and female are known for minor, 
females also for damarense and opacior; all other sexuals remain unknown. 

The pharaonis-complex. A small complex containing the very common cosmopolitan tramp-species 
pharaonis and its two close Indian relatives longi Forel and wroughtoni Forel. In these the cephalic dorsum 
and the alitrunk everywhere is blanketed by fine and very dense reticulate-punctulate sculpture. The eyes 
are slightly in front of the midlength of the sides of the head and are relatively small (0.18-0.21 x HW). 
Antennal scapes are of moderate length, SI 105 or more. The metanotal groove is distinctly impressed. A 
pair of standing hairs is present on the pronotal humeri and usually a single pair also occurs on the 
mesonotum. The first gastral tergite has standing hairs more or less evenly distributed over the sclerite in 
front of the apical transverse row. Colour varies from uniform yellow to dark brown. 

In the Afrotropical region only the bicolor-complex and the opacum-complex show uniform reticulate- 
punctate sculpture on the cephalic dorsum similar to that seen in pharaonis. M. pharaonis separates from 
all species of these two complexes by being smaller (HW 0-40-0-48 as opposed to a combined HW range of 
0-52-0-80 for all species of the bicolor- and opacum-complexes), by being uniformly yellow in colour, and 
by having a single pair of stout standing hairs at the pronotal humeri and another single pair on the 
mesonotum. This combination of characters is not seen in any Afrotropical member of either the 
bicolor-complex or the opacw/n-complex. 

As pharaonis, commonly called Pharaoh's Ant, is now distributed world wide in the tropics, and is very 



334 B. BOLTON 

widely spread in the subtropical and temperate zones in association with human habitations, the region of 
origin of the species has led to considerable differences of opinion. Arnold (1916) postulated South 
America as the original home of pharaonis, but as no close relatives exist there, and as there are very few 
endemic species of Monomorium in the New World (Kempf, 1972), and those which do occur all belong to 
the monomorium-group (DuBois, 1986), Arnold's postulate is improbable and is rejected. 

The Afrotropical region, which has many species of the salomonis-group, was thought by Bernard (1952) 
to be the place of origin of pharaonis. However, his opinion of which species constitute close relatives of 
pharaonis is not accepted here (he included as close relatives ilgii, osiridis, hannonis, setuliferum and 
termitarium) . As no genuine close relatives of pharaonis occur in Africa it is reasonably certain that it is also 
an introduction in the region. 

The most reasonable suggestion, and the one followed here, is that of Emery (1922), who considered 
India to be the most probable place of origin ; a view repeated by Wilson & Taylor (1967) . Having examined 
most extant Monomorium species during the course of this study, I conclude that the closest presently 
detectable living relatives of pharaonis are longi and wroughtoni, both of which are restricted to India, and 
the joint characters of these three form the diagnosis given above. Accepting that the three are close 
relatives and noting that the Indian subcontinent is the only place where all three are found together, it 
seems a reasonable hypothesis that all originated there. It does not of course account for the fact that 
pharaonis has gone on to become perhaps the most successful tramp-species in the world whilst the other 
two are still restricted to India. Sexual forms of pharaonis are known. 

Monomorium afrum Andre 

(Fig. 45) 

Monomorium afrum Andre, 1884: 540. Syntype workers, Sudan: Atbara (Magretti) (MNHN) [examined], 
Monomorium afrum var. asmarensis Forel, 1910a*: 250. Syntype workers, male, Ethiopia: Asmara, 

Ghinda, Nefassit, hi. 1906 (K. Escherich) (MHN; MCZ) [examined]. Syn. n. 
Monomorium afrum var. fultor Forel, 1913a: 332. Syntype workers, Zaire: Shaba, Sankisia, 6.viii.l911 

(Bequaert) (MHN; MRAC) [examined]. Syn. n. 

Worker. TL 3-6-4-3, HL 0-84-1-00, HW 0-66-0-80, CI 78-82, SL 0-72-0-85, SI 103-108, PW 0-46-0-52, 
AL 1-04-1-26 (35 measured). 

Median portion of clypeus with its anterior free margin indented medially, the extent of the indentation 
varying in different populations from a narrow deep notch to a broad and quite deep concavity. Maximum 
diameter of eye 0-24-0-27 x HW, and with 10-12 ommatidia in the longest row. With head in profile the 
posteroventral angles bluntly right-angled or acute and narrowly rounded; not evenly broadly convex (Fig. 
45). Viewed from above and behind the posteroventral occipital angles are prominent and acute. 
Metanotal groove narrowly impressed. Dorsum of propodeum longitudinally impressed, the lateral 
margins of the impression diverging from front to back and frequently represented by a pair of sharp 
carinae, though in others the margins are merely bluntly rounded. Node of petiole in dorsal view with its 
posterior face shallowly transversely concave; degree of concavity varying between samples. Head, 
alitrunk, petiole and postpetiole sharply and densely reticulate-punctate everywhere. First gastral tergite 
finely shagreenate, the sculpture sometimes fading apically on the sclerite. Head without standing hairs on 
dorsal surface behind level of frontal lobes or at most with a single pair mid-dorsally. Alitrunk without 
standing hairs; petiole with one pair, postpetiole with 1-2 pairs of backward directed hairs. First gastral 
tergite hairless except for the apical transverse row; these are usually appressed and may even be absent. 
Colour uniform medium to dark brown, sometimes the gaster darker than the head and alitrunk. 

A widely distributed and very conspicuous species, afrum is easily identified within the salomonis-group 
by the combination of characters noted above . The shape of the posteroventral occipital angles is unique in 
the group and immediately isolates afrum. 

Within the informal aggregation of species termed the o/jacum-complex afrum also separates from two 
other members by its lack of pilosity on the alitrunk, which is present in junodi and albopilosum. Arnold 
(1916) records that afrum forms populous nests in the soil, generally in exposed or sunny situations. 
Wheeler (1922) notes that the ants appeared in large numbers at the carcase of a bird. Whether scavenging 
represents the main feeding method of afrum or whether they are opportunists, both scavenging and 
indulging in active predation when possible, is not known. 

The female of afrum shows some modifications characteristic of the socially parasitic species santschii 
and effractor, and may itself found new colonies by a temporary socially parasitic process. 






SOLENOPSIS GENUS-GROUP 335 

Material examined 

Ethiopia: Neffasit (K. Escherich); Ghinda (K. Escherich); Tessenei (Remedelli); Barentu (Miiller). 
Sudan: Atbara (Magretti); Equatoria, Torit (N. A. Weber). Kenya: Kora (C. West); Kora (Collins & 
Ritchie). Rwanda: Kakitumba (Ross & Leech). Tanzania: Kigoma, Mahale Mts (5. Uehara); Tanga, 
Mwembeni (M. J. Way). Central African Republic: Haut Mbomu (N. A. Weber). Zaire: Shaba, Sankisia 
(Bequaert); Niapu (H. O. Lang); Garamba. Zimbabwe: Bulawayo (G. Arnold). Ivory Coast: Bouake (E. 
Dieme); Ferke. Ghana: Upper Region, Tumu (P. Room); Navrongo (P. Room); Bolgatanga (P. Room); 
Dawhenya (C. A. Collingwood); Amfeda (C. A. Collingwood). 

Monomorium albopilosum Emery 

(Figs 38, 44) 

Monomorium albopilosum Emery, 18956: 24. Syntype workers, South Africa: Bloemfontein, Kimber- 

ley, Makapan (E. Simon); Leribe (Weitzecker) (MCSN) [Kimberley syntypes examined]. 
Monomorium albopilosum var. thales Forel, 19136: 136. Syntype workers, Zimbabwe: Springvale, 

5.x. 1912 (G. Arnold) (BMNH; MHN) [examined]. Syn. n. 
Monomorium (Xeromyrmex) albopilosum st. paucipilosa Santschi, 19196: 235. Syntype workers, South 

Africa: Natal, 1. v. 1898 (Haviland) (NMB) [examined]. Syn. n. 
Monomorium (Xeromyrmex) albopilosum var. clarithorax Santschi, 19196: 235. Syntype workers, South 

Africa: Natal (Haviland) (BMNH; NMB) [examined]. Syn. n. 
Monomorium albopilosum subsp.fingo Arnold, 1946: 61, fig. 13. Syntype workers, South Africa: Cape 

Prov., Albany Dist., Maastricht (J. W. Geyer) (BMNH) [examined]. Syn. n. 

Worker. TL 3-4-4-4, HL 0-80-1-02, HW 0-58-0-78, CI 73-78, SL 0-68-0-90, SI 1 10-120, PW 0-42-0-52, 
AL 1-00-1-32 (30 measured). 

Median portion of anterior clypeal margin concave. Head relatively long and narrow, scapes long (CI 
and SI, above). Eyes of moderate size, the maximum diameter 0-22-0-25 x HW and with 10-12 
ommatidia in the longest row. Petiole node high and conical in profile; in dorsal view the two nodes usually 
of about equal width but sometimes the petiole slightly broader. Sculpture usually of fine dense and sharply 
defined reticulate-punctation all over the head and alitrunk, but sometimes it is reduced on the head 
posteriorly, or on the pronotum, or both. Petiole and postpetiole weakly reticulate-punctate to virtually 
smooth. Gaster shining but first tergite at least with superficial shagreening. Entire body abundantly hairy; 
all dorsal surfaces of head and body with dense standing pilosity and sides of head in full-face view with 
freely projecting hairs both in front of and behind the eyes. Pubescence and pilosity of scapes and tibiae 
elevated, not appressed. Colour uniform light to dark brown, sometimes the gaster slightly darker than the 
head and alitrunk. 

One of only two very densely hairy species within the salomonis-group as it is represented in sub-Saharan 
Africa, the abundant pilosity of albopilosum will isolate this species from all others in the group except 
hirsutum. This latter species, however, shows the strongly contrasting colours of the 6/co/or-complex and 
has a broader head and shorter scapes than in albopilosum; compare the hirsutum CI of 81-83 and SI of 
99-103 with the measurements given above. 

Within the opacum-comp\ex only junodi and albopilosum have hairs present on the dorsal alitrunk, but 
mjunodi these are sparse and do not occur on the propodeum, whereas in albopilosum dense pilosity is 
present everywhere. 

Arnold (1916) characterizes albopilosum as a pugnacious species which stings freely. He adds that the 
nest is in the ground and surrounded by a large low mound of earth. Both alate and apterous females of 
albopilosum are known. 

Material examined 

Malawi: Mlanje (5. A. Neave). Mozambique: Beira (G. Arnold). Zimbabwe: Bulawayo (G. Arnold); 
Springvale (G. Arnold);M.dXopo Hills (G. Arnold). South Africa: Bloemfontein, Kimberley, Makapan (E. 
Simon); Nelspruit (M. Samways); Pretoria (/. C. Faure); Pretoria (C. P. Lounsbury); Natal (Haviland); 
Zululand (R. H. Harris); Mfongosi (W. E. Jones); Cape Prov., Maastricht (/. W. Geyer); Grahamstown 
(F. Jacot-Guillarmod); Grahamstown (Weatherill & Brown). 



336 B. BOLTON 

Monomorium anceps Emery stat. n. 

Monomorium subopacum var. anceps Emery, 18956: 24. Syntype workers, South Africa: Transvaal, 
Hamann's Kraal (E. Simon) (MCSN) [examined]. 

For discussion of this species see under australe. 

Monomorium areniphilum Santschi 
(Figs 46, 51) 

Monomorium salomonis var. areniphila Santschi, 1911: 84. Syntype workers, Tunisia: Gabes, 1906 (A. 

Weiss); Kebili, 1907; Kairouan (Santschi) (NMB) [examined]. 
Monomorium (Xeromyrmex) salomonis var. pullula Santschi, 19196: 235. Syntype workers, Senegal 

(Claveau) (NMB) [examined]. Syn. n. (provisional). 
Monomorium (Xeromyrmex) salomonis var. lepineyi Santschi, 1934: 34, figs 5, 6. Syntype workers, 

Sudan: Nema (de Lepiney) (NMB) [examined]. Syn. n. (provisional). 
Monomorium areniphilum Santschi; Collingwood, 1985: 269. [Raised to species.] 

Worker. TL 3-1^4-3, HL 0-86-1-04, HW 0-67-0-88, CI 78-88, SL 0-68-0-88, SI 98-104, PW 0-40-0-53, 
AL 0-95-1-24 (30 measured). 

Anterior margin of median portion of clypeus evenly shallowly concave. Eyes large, the maximum 
diameter 0-30-0-35 x HW and with 12-14 ommatidia in the longest row. Sides of head evenly shallowly 
convex in full-face view, the occipital margin approximately transverse to broadly but shallowly concave. 
Pronotum and anterior portion of mesonotum in profile evenly convex; median portion of mesonotum flat 
to shallowly convex, sometimes even slightly indented; posterior one-third (approximately) of mesonotum 
suddenly sloping much more steeply to the conspicuously impressed metanotal groove. Highest point of 
propodeal dorsum behind the metanotal groove on a much lower level than the highest point of the 
promesonotum. In dorsal view the propodeum with a narrow flattened median longitudinal strip, the 
dorsum and sides separated by bluntly rounded margins. Dorsum of head with 1-2 pairs of standing hairs, 
which straddle the midline; occipital corners without hairs. Dorsal alitrunk without standing hairs. Petiole 
node with one pair, postpetiole with 2-3 pairs (very rarely with 4 pairs) of backward directed hairs. First 
gastral tergite without standing hairs except for the apical transverse row, or at most with a single pair at or 
near the midlength of the sclerite. Dorsum of head with fine dense reticulate to reticulate-shagreenate 
sculpture; this often extensively overlaid, especially mid-dorsally, by exceptionally fine dense scratch-like 
longitudinal sculpture. Dorsal alitrunk reticulate to shallowly reticulate-punctate, the propodeum more 
strongly sculptured than the pronotum; intensity of sculpture variable between series. First gastral tergite 
at least with superficial reticular patterning, more often this is overlaid by a secondary fine shagreening. 
Colour brown, very variable in shade. 

I am grouping the names areniphilum, lepineyi and pullulum as a single species here, based on the 
following combination of five characters within the Salomon is-group. 

Eyes both relatively and absolutely large (see measurements above). 

Antennal scapes of moderate length (SI 98-104). 

Characteristic outline shape of dorsal alitrunk (Fig. 46). 

Cephalic sculpture (as described above). 

Very reduced dorsal pilosity (as described above). 

M. areniphilum appears to be a successful circum-Saharan species which shows variation in colour and 
size over its wide range but which seems consistent in the characters noted above. It is accepted that the 
name as now applied may conceal two or more close but discrete sibling species, but only a detailed 
investigation of the North African fauna, with its welter of unresolved infraspecific names attached to 
salomonis and its relatives, will be able to resolve the confusion. I am unable to undertake such a study 
here, so for the present I regard lepineyi and pullulum provisionally as junior synonyms of areniphilum, 
fully realizing that this situation may change once detailed taxonomic investigation is possible. 

The single lepineyi syntype available for study matches areniphilum moderately well, but is smaller and 
darker in colour, being a uniform blackish brown, and has the head narrower than the areniphilum 
syntypes. The eyes in the lepineyi syntype are slightly larger than in areniphilum and the sides of the head 
are not as distinctly convergent posteriorly. 

The syntypes of pullulum are relatively large specimens but their indices are within the areniphilum 
range. These syntypes are uniformly dark brown on the head and alitrunk but have a blackish brown gaster. 
The cephalic sculpture in pullulum, whilst of the same form as in areniphilum, tends to be denser. 



SOLENOPSIS GENUS-GROUP 337 

Essential measurements and indices of the syntypes of the three names now provisionally regarded as 
synonymous are as follows. 





HW 


CI 


SL 


SI 


Size of eye 


number 


pullulum 


0-86-0-88 


83-85 


0-86-0-88 


99-102 


0-30 x HW 


3 


areniphilum 


0-76-0-81 


84-88 


0-76-0-81 


99-100 


0-30 x HW 


3 


lepineyi 


0-67 


78 


0-68 


101 


0-33 x HW 


1 



Material examined 

Egypt: Siwa (J. Omer-Cooper). Sudan: Nema (de Lepiney); Khartoum (R. Cottam); Khartoum (J. 
Cloudsley -Thompson). Tunisia: Gabes (A. Weiss); Kebili (Santschi). Algeria: Adrar (P. Room); Bordj 
Moctar (P. Room); Ahaggar, Tamsuejat (Meinertzhagen). Mali: Gao (B. Malkin); Gao (P. Room); 
Bourem (P. Room); Tessalit (P. Room); Anefis (P. Room); Labezanga (P. Room). Niger: Ayorou (P. 
Room); Assango (J. Newby). Senegal: no loc. (Claveau). 

Monomorium australe Emery 

Monomorium subopacum r. australe Emery, 1886: 363. Syntype workers. South Africa: Cape of Good 

Hope (L. Peringuey) (MCSN; MR AC) [examined]. 
Monomorium subopacum r. australe var. laeviceps Emery, 1886: 364. Syntype workers, South Africa: 

Cape of Good Hope (L. Peringuey) (MCSN). [Unavailable name.] 
Monomorium (Paraholcomyrmex) [sic] australe Emery; Santschi, 1917: 282. [Raised to species but 

misidentified and placed in wrong subgenus.] 

As the three names australe, anceps and termitarium constitute a very close triad which may represent 
only one real species, the usual format of the revision is abandoned here so that the three may be 
considered together. 

These three southern African forms are retained for the present as separate species until more material is 
collected for study, at which time it may be possible to show whether they are indeed separate or whether 
two or all of them are synonymous. All three are represented only by short syntypic series at the time of 
writing. The three together are characterized by the following snared characters within the salomonis- 
group. 

Relatively small forms, their combined dimensions being TL 2-4-2-6, HL 0-60-0-66, HW 0-46-0-52, CI 
75-79, SL 0-47-0-54, SI 100-104, PW 0-30-0-35, AL 0-68-0-76. Maximum diameter of eye 0-24-0-26 x 
HW and with 7-9 ommatidia in the longest row. [Note that this combined range of dimensions is no greater 
than those frequently encountered in what are indubitably single species elsewhere in this species-group.] 
Head with feebly developed shagreenate-granular sculpture so that the cephalic dorsum appears weakly 
shining and semi-smooth. Dorsal alitrunk lacking standing hairs of any description. Petiole with a single 
pair of backward directed hairs, postpetiole with 1-2 pairs of hairs. First gastral tergite with 2-3 pairs of 
hairs in front of the apical transverse row, the hairs confined to the basal half of the sclerite. 

Within the limits of this diagnosis the dimensions of the three are as follows. 
M. termitarium syntypes, TL 2-5-2-6, HL 0-60-0-64, HW 0-46-0-51 , CI 75-79, SL 0-48-0-53, SI 100-104, 
PW 0-30-0-35, AL 0-70-0-76; maximum diameter of eye 0-24-0-25 x HW, with 7-8 ommatidia in the 
longest row (6 measured). 

M. australe syntypes, TL 2-5-2-6, HL 0-64-0-66, HW 0-50-0-52, CI 78-79, SL 0-50-0-54, SI 100-104, PW 
0-32-0-34, AL 0-74-0-76; maximum diameter of eye 0-25-0-26 x HW, with 9 ommatidia in the longest 
row (4 measured). 

M. anceps syntypes, TL 2-4, HL 0-60, HW 0-47, CI 78, SL 0-47, SI 100, PW 0-30, AL 0-68; maximum 
diameter of eye 0-26 x HW, with 7-8 ommatidia in the longest row (2 measured). 

Characters which presently serve to isolate the three syntypic series include colour, sculpture and gastral 
pilosity, but all are weak and may prove to be gradient. For the present the differentiation is as follows. 

M. termitarium is a uniformly yellow species from Botswana in which the mesonotal dorsum is 
superficially reticulate-punctate. The pronotal dorsum is similarly sculptured but the sculpture is more 
reduced and somewhat effaced so that the punctures are vestigial. In other words the pronotal dorsal 
sculpture is obviously a reduced and effaced version of that seen on the mesonotum. Two pairs of hairs are 
present on the basal half of the first gastral tergite. 

M. australe, from Cape Province, South Africa, is a medium brown species with a darker brown gaster. 
Dorsal alitrunk sculpture corresponds with the above, being reticulate-punctate on the mesonotum and 
feebly reticulate on the pronotum, again the pronotal sculpture obviously a reduced and effaced version of 



338 B. BOLTON 

the mesonotal. The syntypes show varying degrees of abrasion but it appears that two pairs of hairs occur 
on the basal half of the first gastral tergite. 

M. anceps, from Transvaal, South Africa, is medium brown with a darker brown gaster. The mesonotal 
dorsum is sharply reticulate-punctate whilst the pronotal dorsum is finely shagreenate. In other words the 
two areas show distinctly contrasting sculpture and the pronotal component does not appear to be merely a 
reduced and effaced version of that seen on the mesonotum. Three pairs of hairs occur on the basal half of 
the first gastral tergite. 

Apart from their original descriptions, subsequent inclusion in Arnold (1916), and their later appear- 
ances in catalogues and lists, no further comments on the taxonomy of anceps or termitarium occur 
anywhere in the literature. 

Arnold (1916: 224-225) reproduced a translation of the original description of anceps and termitarium, 
and presented a redescription of australe which is certainly based on misidentified material as his specimens 
were much larger (TL 3-3-3-8) than the syntypes. Mysteriously he gave australe in his key (p. 205) as 
having a fairly well-defined median ocellus present, but does not mention this in the description. It is most 
probable that Arnold did not see the australe syntypes, where ocelli are absent, and that this material refers 
to the specimens later described as ocellatum. 

Santschi (1917) redescribed australe and elevated it to the status of a valid species, but transferred it to 
the destructor-group (= subgenus Parholcomyrmex) . From his notes and description it is obvious that he 
thought the australe syntypes to be part of a polymorphic species, and considering his description it seems 
most likely that the major workers which he described (provided by Arnold and perhaps also specimens 
referred to australe by Arnold, 1916) are havilandi; certainly they are not conspecific with the australe 
syntypes. In the same paper Santschi gives havilandi as a stirps of australe. The type-material of havilandi is 
radically different from that of australe, belonging to another species-group, but does bear some 
resemblance to members of the destructor-group, which reinforces the conclusion that Santschi's (1917: 
282-284) interpretation of australe is a misidentification. 

In summary, australe and its close relatives anceps and termitarium, are members of the salomonis-group 
and may represent only a single species, but more material is necessary before any sound conclusions can 
be drawn. 

Material examined 

South Africa: Transvaal, Hamann's Kraal (E. Simon); Cape of Good Hope (L. Peringuey). Botswana: 
Kalahari, Kooa (L. Schultze). 

Monomorium bicolor Emery 

Monomorium bicolor Emery, 1877: 368. Syntype workers, Ethiopia: Sciotel, Bogos, 1870 (O. Beccari) 

(MCSN; MRAC) [examined]. 
Monomorium bicolor var. coerulescens Santschi, 1912: 148. Holotype worker, Djibouti: Obock, 1893 (M. 

Maindron) (MNHN) [examined]. [Synonymy by Santschi, 1914c: 353.] 
Monomorium bicolor var. rufibasis Santschi, 1914c: 353. Syntype workers, Egypt: Upper Egypt (diagnosis 

in key) (not in NMB, presumed lost). Syn. n. 
[Monomorium bicolor var. rufobasalis Santschi; Santschi, 1926a: 240. Misspelling of bicolor var. rufibasis 

Santschi, 1914c: 353.] 
Monomorium (Xeromyrmex) bicolor var. uelense Santschi, 1926a: 239. Syntype workers, Zaire: Haut 

Uele, Moto, 1920 (L. Burgeon) (NMB; MRAC) [examined]. Syn. n. 
[Monomorium (Xeromyrmex) bicolor var. uluense Santschi; Santschi, 1926a: 240. Misspelling of bicolor 

var. uelense Santschi, 1926a: 239. The spelling uluense occurs on the syntype data labels but uelense is the 

original orthography.] 
Monomorium (Xeromyrmex) bicolor war . aequatoriale Santschi, 1926a: 240. Syntype workers, Cameroun: 

Gr. Batanga, 1911 (Schwab), (Wasmann) (NMB) [examined]. Syn. n. 
Monomorium (Xeromyrmex) bicolor wax. tropicale Santschi, 1926a: 240. Syntype workers, female, Zaire: 

Stanleyville (Majella) (NMB) [examined]. Syn. n. 

Worker. TL 3-2-3-9, HL 0-70-0-93, HW 0-52-0-75, CI 73-83, SL 0-56-0-78, SI 104-115, PW 0-36-0-50, 
AL 0-82-1-20 (25 measured). 

Third and fourth (basal) tooth of mandible approximately the same size or the fourth very slightly 
smaller than the third, but the basal tooth never reduced to a minute denticle. Median portion of clypeus 
with its anterior free margin usually indented, more rarely the margin approximately transverse but never 
with flanking sharp teeth. Eyesof moderate size, the maximum diameter 0-24-0-27 x HW. Ventral surface 






SOLENOPSIS GENUS-GROUP 339 

of head with curved simple hairs but lacking extremely long J-shaped ammochaete hairs. Dorsal alitrunk 
hairless, petiole with one pair and postpetiole with 1-2 pairs of posteriorly directed hairs. Discounting the 
apical transverse row the first gastral tergite usually with only 1-2 pairs of hairs, situated on the basal half; 
rarely 3-4 pairs of hairs present. Dorsum and sides of head and entirety of alitrunk densely and sharply 
reticulate-punctate. Gaster usually finely and densely shagreenate dorsally but the sculpture may fade 
posteriorly in some examples and is reduced in a few. Colour bright orange to red on the head and alitrunk, 
the gaster blackish brown to black, the two strongly contrasting. First gastral tergite frequently with an 
anteromedian paler area. 

The most successful and widely distributed species of its group in the Afrotropical region, bicolor also 
extends it range into the drier zones of southern Palaearctic, being found in North Africa and Saudi Arabia. 
In sub-Saharan Africa bicolor is characteristically a species of open savannah or semi-arid zones, but it also 
occurs in forested areas where there is some direct insolation, often being found on forest paths in Nigeria 
and Ghana. Nests are constructed directly into the earth and the species appears to be a general scavenger 
in habits, quickly appearing in traps baited with crushed large insects. 

In the bicolor-comp\ex bicolor is characterized by the features listed above, differing from its closest 
relatives in that it lacks the densely hairy alitrunk seen in hirsutum, has much smaller eyes than personation 
(0-31-0-33 x HW), lacks the reduced basal mandibular tooth of rufulum, lacks the pair of sharp clypeal 
teeth characteristic of westi, and lacks the dense gastral pilosity of dictator. 

Material examined 

Ethiopia: Gamo, Konso (H. Scott); Sciotel, Bogos (O. Beccari); Eritrea, Ailet {Miiller). Sudan: 
Khartoum (R. Cottam); Shamba (J. E. Mellor); Kadugli (C. Sweeny). Djibouti: Obeck (M. Maindron). 
Kenya: Kora (C. West); Kora (Collins & Ritchie). Liberia: Monrovia. Burkina Faso: Ougadougou (P. 
Room). Ghana: Mole Game Res. (J. C. Grieg); Mampong (P. Room); Bolgatanga (P. Room); Tumu (P. 
Room). Nigeria: Gambari (B. Bolton); Gambari (B. Taylor); nr Lake Chad (J. C. Deeming); Bakura (E. 
A. Mill); Sokoto (E. A. Mill); Mokwa (C. Longhurst). Togo: Tove (B. Dufour). Cameroun: Gr. Batanga 
(Schwab); Metet (Schwab); Nkoemvon (D. Jackson). Zaire: Haut Uele, Moto (L. Burgeon), Kisangani 
(Majella); Kisangani (N. A. Weber); Ituri For., Beni Irumu (N. A. Weber). 

Monomorium carbo Forel stat. n. 

Monomorium salomonis var . carbo Forel, 1910d: 251. Syntype workers, Ethiopia: Ghinda (K. Escherich) 
(MHN) [examined]. 

Worker. TL 2-3-2-4, HL 0-60-0-63, HW 0-43-0-45, CI 71-72, SL 0-44-0-48, SI 102-107, PW 0-30-0-31, 
AL 0-66-0-70 (2 measured). 

Anterior margin of median portion of clypeus shallowly concave. With head in full-face view the sides 
weakly divergent from back to front, the occipital margin shallowly concave. Maximum diameter of eye 
0-24-0-26 x HW and with 7 ommatidia in the longest row. The eyes very slightly in front of the midlength 
of the sides. Metanotal groove scarcely impressed in profile, the propodeal dorsum flattened to weakly 
depressed medially, without sharp lateral margins. Occipital margin of head with a pair of hairs straddling 
the midline and another pair closer to the occipital corners. Dorsal alitrunk without hairs. Petiole and 
postpetiole each with 1-2 pairs of backward directed hairs. First gastral tergite with numerous hairs which 
are evenly distributed over the surface in front of the apical transverse row. Dorsum of head opaque, 
shagreenate-punctulate everywhere. Dorsal alitrunk finely reticulate-punctate, the sides similarly sculp- 
tured but somewhat effaced on the sides of the pronotum. First gastral tergite shining, with superficial 
reticular patterning only. Colour uniform dark brown to blackish brown. 

This enigmatic Ethiopian species is only known from the type-series of a couple of workers. At first 
glance it appears to be related to minor, a yellow species from Namibia and Angola which itself seems to be 
intermediate between this complex and the v/afor-complex, but the wide separation of their habitats and 
the differences in their scape indices stand against this apparent relationship. Fresh material will have to be 
obtained before a clear picture of what constitutes carbo can be developed. 

Material examined 
Ethiopia: Ghinda (K. Escherich). 

Monomorium dakarense Santschi stat. n. 

Monomorium bicolor st. dakarensis Santschi, 1914c: 353. Syntype workers, Senegal: Longa (Roubaud) 
(NMB) [examined]. [Diagnosis in key.] 



340 B. BOLTON 

Worker. TL 2-2-2-3, HL 0-57-0-59, HW 0-44-0-47, CI 77-80, SL 0-44-0-45, SI 95-100, PW 0-30-0-31, 
AL 0-66-0-70 (3 measured). 

Maximum diameter of eye 0-23-0-24 x HW, with 7-8 ommatidia in the longest row. Distribution of 
pilosity as in bicolor but first gastral tergite with numerous standing hairs in front of the apical transverse 
row. Head under low magnification appearing uniformly finely granular; under higher magnification the 
entire dorsum opaque, very finely and densely punctulate-shagreenate and having a silky appearance. 
Alitrunk, petiole and postpetiole finely densely reticulate-punctate. First gastral tergite shagreenate. Head 
and alitrunk orange-yellow to dull orange-brown, the gaster blackish brown, the two colours strongly 
contrasting. 

Associated with bicolor until the present, dakarense is best regarded as a distinct species. Apparently it 
was linked to bicolor by Santschi (1914c) purely on the grounds of their similar colour, but he separated 
them by saying that in dakarense the scape was shorter and the psammophore better developed. The scape 
is indeed snorter in dakarense (SI 95-100) than in bicolor (SI 104-115), but also the former is considerably 
smaller (compare the measurements above with bicolor HL 0-70-0-93, HW 0-52-0-75, SL 0-56-0-78). The 
cephalic sculpture of bicolor is composed of sharply defined reticulate-punctation everywhere, and the first 
gastral tergite is less densely hairy. 

M. dakarense is separated from its immediate allies by combining the distinctive colour scheme of the 
6/co/or-complex with a lack of the reticulate-punctate cephalic sculpture usually associated with that colour 
scheme, replacing it by the silky punctulate-shagreenate sculpture generally associated with sutu and its 
close relatives in the australe-compAex. It is thus difficult to decide if dakarense is a member of the 
bicolor-comp\ex (because of its colour) which has independently acquired the cephalic sculpture typical of 
sutu and allies, or if it is a member of the australe-complex which has acquired the 6/co/or-complex colour 
scheme. For the present I incline towards the latter as dakarense seems closer morphologically to opacior, 
parvinode and minor than it does to any member of the 6/co/or-complex. 

Material examined 

Senegal: Longa (Roubaud). 

Monomorium da mare use Forel stat. n. 

Monomorium salomonis subsp. damarense Forel, 1910c: 17. Syntype workers, Namibia: Damaraland, 

Gawieb (L. Schultze) (MHN) [examined]. 
Monomorium salomonis var. unicolor Stitz, 1923: 156. Syntype worker (lacking head), Namibia: 

Omaruru, 21-22. vi. 1911 (Michaelsen) (MNHU) [examined]. Syn. n. 

Worker. TL 2-2-2-8, HL 0-58-0-68, HW 0-42-0-51, CI 72-75, SL 0-48-0-59, SI 110-116, PW 0-29-0-34, 
AL 0-66-0-80 (12 measured). 

Median portion of clypeus with anterior margin transverse to shallowly concave. Maximum diameter of 
eye 0-27-0-31 x HW, with 7-9 ommatidia in the longest row. Scapes relatively long (SI > 105), longer than 
any other species included in the australe-comp\ex. Metanotal groove feebly impressed in profile. Dorsum 
of head without standing hairs behind the level of the frontal lobes. Dorsal alitrunk without standing hairs. 
Petiole node without hairs but postpetiole with a single backward directed pair. First gastral tergite with 
minute appressed pubescence but usually without hairs except for the apical transverse row. Dorsum of 
head opaque, blanketed with very fine and dense reticulate-shagreenate to striolate-punctulate or 
granulate-punctulate sculpture; close to the occipital margin the sculpture may appear feebly reticulate- 
punctulate. Pronotal dorsum finely reticulate, the sculpture becoming more intense posteriorly on the 
dorsal alitrunk so that the propodeum is superficially reticulate-punctulate. First gastral tergite with 
superficial reticular patterning, which is overlaid by fine shagreening basally. Colour light brown to 
medium brown. 

The extremely reduced dorsal pilosity coupled with the relatively strong cephalic sculpture and long 
scapes render this Namibian and Botswanan species easily recognisable. Namibian samples uniformly lack 
hairs on the first gastral tergite in front of the apical row, but a short series from Serowe in Botswana has a 
single short pair at about the midlength of the sclerite. Whether this series should be regarded as a separate 
species cannot be decided at present because of shortage of material with which to assess the stability of the 
character. 

Material examined 

Namibia: Damaraland, Gawieb (L. Schultze); Omaruru (Michaelsen); Kuiseb Riv., nr Gobabeb (A. C. 
Marsh); Namib Desert, 15° 36' E, 23° 04' S (A. C. Marsh). Botswana: Serowe (P. Forchhammer) . 



SOLENOPSIS GENUS-GROUP 341 

Monomorium delagoense Forel 

Monomorium salomonis st. delagoense Forel, 1894a: 87. Syntype workers, Mozambique: Delagoa 

(= Maputo) (Liengme) (BMNH; MHN) [examined]. 
Monomorium salomonis r. delagoense var. grahamstownensis Forel, 1914: 245. Syntype workers, South 

Africa: Cape Prov., Grahamstown (MHN) [examined]. [Unavailable name.] 
Monomorium delagoense Forel; Santschi, 1928: 192. [Raised to species.] 
Monomorium delagoense var . lacrymans Arnold, 1944: 15, fig. 19. Syntype workers, South Africa: Natal, 

Weenen (H. P. Thomasset) (BMNH) [examined]. Syn. n. 

Worker. TL 3-1-3-9, HL 0-72-0-92, HW 0-58-0-77, CI 80-85, SL 0-56-0-70, SI 88-95, PW 0-40-0-50, 
AL 0-84-1-08 (20 measured). 

Anterior free margin of median portion of clypeus evenly concave . Eyes of moderate size , the maximum 
diameter 0-22-0-24 x HW and with 9-1 1 ommatidia in the longest row. Dorsum of head with 3-4 pairs of 
standing hairs behind the level of the frontal lobes. Dorsal alitrunk with a single pair of long hairs at the 
pronotal humeri, but otherwise hairless. Petiole node with one pair and postpetiole with 2-3 pairs of 
backward directed hairs, the first gastral tergite with numerous hairs which are more or less evenly 
distributed over the entire sclerite. Dorsum of head finely shagreenate to superficially reticulate every- 
where, usually with fine longitudinal striolation between and immediately behind the frontal lobes. 
Alitrunk finely and densely reticulate-punctate everywhere, the promesonotal dorsum distinctly more 
strongly sculptured than the cephalic dorsum behind the level of the eyes. Petiole and postpetiole finely 
reticulate-punctate. First gastral tergite usually with fine superficial reticulation only, but sometimes this is 
absent, leaving the surface featureless. Sometimes the superficial reticulation is denser basally and fades 
out posteriorly on the sclerite . Colour uniform medium to dark brown , or with the gaster somewhat darker 
than the head and alitrunk. 

The only member of the subopacum-complex to possess standing hairs on the dorsal alitrunk , delagoense 
is also the species which links the opacum-complex to the subopacum-comp\ex . It is very close to junodi but 
is distinguishable by its reduced cephalic sculpture, which is much less strongly developed than on the 
promesonotum. In junodi the head and promesonotum are approximately evenly sculptured, both areas 
being densely reticulate-punctate. Most populations of junodi tend to have more than one pair of hairs on 
the dorsal alitrunk, although in some only the pair at the pronotal humeri is present. In delagoense hairs 
behind the humeral pair are apparently never developed. 

Material examined 

Mozambique: Maputo (Liengme). South Africa: Natal, Weenen (H. P. Thomasset); Natal (Haviland); 
Pietermaritzburg (G. Arnold); Mkuzi Reserve (C. Peeters); Cape Prov., Grahamstown (G. Baines); 
Grahamstown (W. L. Brown); Grahamstown (/. Hewitt); Grahamstown (Weatherill & Brown). 

Monomorium dictator Santschi stat. n. 

Monomorium (Xeromyrmex) bicolorst. dictator Santschi, 1937: 222, figs 20, 21. Syntype workers, female, 

Angola: Ebanga, 1932-33 (A. Monard) (NMB) [examined]. 
Monomorium (Xeromyrmex) bicolor st. personatum var. impuriceps Santschi, 1937: 222. Syntype 

workers, Angola: Ebanga, 1932-33, no. 117-136 (A. Monard) (NMB) [examined]. [Unavailable 

name.] 

Worker. TL 2-9, HL 0-74-0-76, HW 0-57-0-59, CI 77-78, SL 0-62-0-63, SI 107-109, PW 0-40, AL 0-86 
(3 measured). 

Third and fourth (basal) tooth of mandible subequal in size, the latter very slightly smaller than the 
former but not reduced to a minute denticle. Median portion of clypeus with its anterior free margin 
shallowly concave and flanked by rounded blunt angles, without projecting sharp teeth at the apices of the 
clypeal carinae. Eyes of moderate size, the maximum diameter about 0-25 x HW and with 9-10 ommatidia 
in the longest row. Dorsal alitrunk without hairs but the first gastral tergite conspicuously pilose, with 6-8 
pairs of evenly distributed hairs on the sclerite in front of the apical transverse row. Entirety of head and 
alitrunk reticulate-punctate. Head and alitrunk red to orange-red, the gaster blackish brown to black, 
without an orange or reddish patch mediobasally. 

M. dictator is closely related to bicolor and rufulum. It separates from the former by having the gaster 
much more densely hairy than in bicolor, and dictator lacks the very reduced fourth (basal) tooth on the 



342 B. BOLTON 

mandible, which is characteristic of rufulum. Other members of the bicolor-comp\ex, characterized 
together by their possession of dense reticulate-punctate sculpture on the head and alitrunk, and 
bicoloured body with the gaster blackish brown to black and the head and alitrunk reddish, separate from 
dictator as follows. 

M. westi, presently known only from Kenya, has the two longitudinal clypeal carinae terminating in 
freely projecting sharp teeth, not developed in dictator. M. personation, a species sympatric with dictator, 
has much larger eyes whose maximum diameter is 0-31—0-33 x HW, as opposed to 0-25 x HW in dictator. 
M. hirsutum, known only from Ethiopia, has the dorsal alitrunk densely hairy; in dictator the alitrunk lacks 
standing hairs. 

Material examined 
Angola: Ebanga (A. Monard). 

Monomorium disertum Forel stat. n. 

Monomorium salomonis var. diserta Forel, 1913c: 216. Syntype workers, Zimbabwe: Shiloh, 10. v. 1913, 

no. 172 (G. Arnold) (BMNH; MHN) [examined]. 
Monomorium (Xeromyrmex) termitarium st. disertum var. petulans Santschi, 1928: 194. Syntype workers, 

Zimbabwe: Sawmills, ll.vii.1920 (G. Arnold) (NMB) [examined]. [Unavailable name.] 

Worker. TL 2-0-2-2, HL 0-52-0-60, HW 0-41-0-48, CI 77-81, SL 0-38-0-43, SI 89-93, PW 0-28-0-31, 
AL 0-58-0-64 (9 measured). 

Anterior margin of median portion of clypeus transverse to shallowly concave. Sides of head extremely 
weakly convex in full-face view, the occipital margin very shallowly concave. Antennal scapes relatively 
short, SI<95. Maximum diameter of eye 0-25-0-27 x HW, with 7-9 ommatidia in the longest row. 
Metanotal groove feebly impressed. Dorsum of head apparently with a single pair of standing hairs behind 
the level of the frontal lobes, situated just behind the level of the eyes. The available material is abraded 
and a second pair may be present close to the occipital margin. Dorsal alitrunk without hairs. Petiole node 
without hairs, the postpetiole with one backward directed pair. First gastral tergite with a single pair of 
standing hairs in front of the apical transverse row, situated approximately at the midlength of the sclerite. 
Head very finely shagreenate to reticulate-shagreenate, mid-dorsally usually with extremely fine longitu- 
dinal striolate markings. Pronotal dorsum finely shagreenate to reticulate-shagreenate, the sculpture 
becoming more obviously reticulate to reticulate-punctate on the propodeum. First gastral tergite with 
superficial reticular patterning only. Colour pale brownish yellow, the gaster sometimes slightly darker 
than the alitrunk. 

A small yellowish species which seems related to australe and its immediate allies, disertum differs from 
them by having relatively shorter scapes and lacking backward directed hairs on the petiole node. Apart 
from this disertum appears to have only a single pair of standing hairs on the first gastral tergite in front of 
the apical transverse row, whereas australe and allies have 2-3 pairs. 

Material examined 
Zimbabwe: Shiloh (G. Arnold); Sawmills (G. Arnold); Birchenough Bridge (G. Arnold). 

Monomorium drapenum sp. n. 

(Fig. 48) 

Holotype worker. TL 2-4, HL 0-65, HW 0-50, CI 77, SL 0-50, SI 100, PW 0-32, AL 0-68. 

Anterior free margin of median portion of clypeus shallowly convex. Eyes relatively large , the maximum 
diameter 0-28 x HW. Sides of head in full-face view evenly shallowly convex, broadest at the level of the 
eyes and narrowing slightly both anteriorly and posteriorly; occipital margin broadly but shallowly 
concave. With the alitrunk in profile the pronotal dorsal outline feebly convex, the mesonotum more or less 
flat and sloping shallowly to the weakly impressed metanotal groove. Propodeum in dorsal view feebly 
transversely concave at the curvature where dorsum meets declivity. Petiole and postpetiole of approxi- 
mately equal width in dorsal view; in profile the petiole node slightly higher than the postpetiole. Anterior 
peduncle of petiole ventrally with a broad blunt lamelliform process. Dorsum of head behind level of 
frontal lobes with appressed sparse pubescence and with four pairs of standing hairs, of which three pairs 
are close to the midline and the fourth is situated on the occipital margin close to the corners. Dorsal 
alitrunk without standing hairs, with fine sparse appressed pubescence present. Petiole with one pair and 



SOLENOPSIS GENUS-GROUP 343 

postpetiole with two pairs of backward directed hairs. First gastral tergite with hairs evenly distributed over 
the surface of the sclerite. Cephalic dorsum polished and shining, sculpture from level of eyes to occipital 
margin consisting only of an extremely fine superficial reticular patterning. Dorsal alitrunk more strongly 
sculptured than the head, the sculpture increasing in intensity from front to back. Pronotum superficially 
reticulate, grading on the mesonotum into raised reticulation and weak reticulate-punctate sculpture 
posteriorly; propodeal dorsum reticulate-punctate. Sides of pronotum polished and weakly reticulate- 
shagreenate, the remainder finely reticulate-punctate. Petiole and postpetiole reticulate to weakly 
reticulate-punctulate. First gastral tergite superficially reticulate, the patterning denser basally than 
apically. Head and gaster dark brown, alitrunk, petiole and postpetiole medium brown. 

Paratype workers. TL 2-4-2-6, HL 0-60-0-67, HW 0-46-0-52, CI 73-78, SL 0-46-0-51, SI 98-104, PW 
0-32-0-34, AL 0-68-0-72 (18 measured). Maximum diameter of eye 0-28-0-32 x HW, with 8-10 ommati- 
dia in the longest row. As holotype but some samples uniformly dark brown and some individuals with the 
subpetiolar process more acute than in the holotype, appearing more dentiform than lobate. Postpetiole 
sometimes with only a single pair of hairs. 

Holotype worker, Namibia: Namib Desert, 15° 36' E, 23° 04' S, sample P 18, pitfall, 1984 (A. C. Marsh) 
(BMNH). 

Paratypes. 8 workers with same data as holotype; 6 workers with same data but 15° 13' E, 23° 06' S, 
sample P 15; 3 workers with same data but 15° 36' E, 23° 04' S, sample P 14; 3 workers with same data but 
15° 36' E, 23° 04' S, sample P 22; 3 workers with same data but 15° 18' E, 23° 06' S, sample P 23; 3 workers 
with same data but 15° 24' E, 23° 06' S, sample P 24; 3 workers with same data but 15° 24' E, 23° 06' S, 
sample P 25 (BMNH; MHN; MCZ). 

Non-paratypic material examined. Namibia: Namib Desert, Mirabib, sample 192 (A. C. Marsh). 

This distinctive small Namib Desert species is quickly identified by its sculpture, distribution of pilosity, 
and presence of a conspicuous lobate to dentiform subpetiolar process. 

Monomorium esharre sp. n. 

Holotype worker. TL 1-9, HL 0-52, HW 0-40, CI 77, SL 0-38, SI 95, PW 0-27, AL 0-56. 

Median portion of clypeus with anterior margin shallowly convex. Eyes situated slightly in front of 
midlength of sides; maximum diameter of eye 0-25 x HW and with 7 ommatidia in the longest row. In 
full-face view the sides of the head weakly convergent behind the eyes and the occipital margin shallowly 
concave. Promesonotal dorsum evenly feebly convex in profile, the metanotal groove not impressed but 
the propodeal dorsum on a lower level than that of the mesonotum. Dorsum of head without standing hairs 
behind the level of the frontal lobes. Dorsal alitrunk without standing hairs. Petiole node without hairs but 
postpetiole with a single backward directed pair. First gastral tergite with an apical transverse row of hairs 
but without standing hairs on the tergite in front of this. Cephalic dorsum sculptured with faint superficial 
reticular patterning only. Pronotal dorsum finely reticulate to reticulate-shagreenate, the mesonotal 
dorsum similar; propodeal dorsum finely reticulate-punctulate to reticulate-granular. First gastral tergite 
with superficial reticular patterning only. Head and gaster blackish brown, the alitrunk somewhat lighter 
brown. 

Paratype workers. TL 1-9-2-0, HL 0-52-0-54, HW 0-40-0-42, CI 77-78, SL 0-38, SI 90-95, PW 
0-26-0-27, AL 0-56 (2 measured). Maximum diameter of eye 0-24-0-25 x HW and with 7 ommatidia in the 
longest row. Otherwise as holotype. 

Holotype worker, Namibia: Namib Desert, 15° 36' E, 23° 04' S, pitfall, sample P 17, 1984 (A. C. Marsh) 
(BMNH). 

Paratypes. 2 workers with same data as holotype (BMNH; MCZ). 
Non-paratypic material examined. Namibia: Namib Desert, 15° 36' E, 23° 04' S, sample P 20 (A. C. 
Marsh). As holotype but lighter in colour, medium brown with the gaster darker. The head and alitrunk are 
approximately the same shade. 

All six small species in the mediocre-complex show relatively feeble or very reduced cephalic sculpture 
and almost non-existent dorsal pilosity. Of the six nirvanum retains a single pair of backward directed hairs 
on the petiole, which is absent in the remainder. M. rabirium, osiridis and zulu have eyes which are situated 
distinctly in front of the midlength of the sides of the head. The two remaining, mediocre and esharre, are 
separated by the characters noted in the key and under mediocre. 



344 B. BOLTON 

Monomorium excelsior Arnold stat. n. 

Monomorium tchelichofi var. excelsior Arnold, 1926: 227. Syntype workers, males, South Africa: Cape 
Prov., Matroosberg, Hex River Mts, 5500-7000 ft (= 1677-2134 m), i.1917 (R. W. Tucker) (BMNH) 
[examined]. 

Monomorium (Xeromyrmex) speculiceps Santschi, 1928: 191, fig. 3a. Holotype worker, South Africa: 
Cape Prov., Hermanus (Lockee-Bayne) (NMB) [examined]. Syn. n. 

Worker. TL 3-3-3-5, HL 0-84-0-92, HW 0-64-0-72, CI 76-80, SL 0-78-0-82, SI 114-122, PW 0-42-0-47, 
AL 0-96-1-06 (5 measured). 

Anterior margin of median portion of clypeus transverse to extremely shallowly concave in full-face 
view, never notched medially. Eyes of moderate size, the maximum diameter 0-22-0-25 x HW and with 10 
ommatidia in the longest row. Antennal scapes relatively long, SI > 110. Alitrunk appearing long and low 
in profile, the promesonotal dorsum forming an even shallow convexity from front to back and sloping 
posteriorly to the weakly impressed metanotal groove. Petiole node cuneate in profile, narrowly rounded 
above. Cephalic dorsum behind the frontal lobes with 3-4 pairs of hairs straddling the midline, the occipital 
margin with a further 2-3 pairs arranged in a roughly transverse row; the outermost of these hairs very 
close to the occipital corner. A single pair of relatively long standing hairs present at the pronotal humeri 
and another, shorter, pair situated anteriorly on the mesonotal dorsum. Petiole node with one pair of 
backward directed hairs, postpetiole with 3-4 pairs. First gastral tergite with standing hairs numerous and 
distributed more or less evenly over the sclerite. Head smooth and very glossy, sculptured only with faint 
vestiges of fine superficial reticular patterning. Pronotal dorsum with superficial reticular patterning or 
with feeble reticulation. Mesonotum as pronotum or the reticulation somewhat more distinct. Propodeal 
dorsum weakly shagreenate-punctulate. Sides of alitrunk reticulate to reticulate-shagreenate, the pro- 
notum much more weakly sculptured than the remainder. First gastral tergite unsculptured or with faint 
superficial reticulate patterning basally. Colour glossy chestnut-brown. 

First described by Arnold (1926) as a variety of tchelichofi, excelsior clearly ranks as a separate species. 
Not only do the two have very different distributions of pilosity but also their dimensions show marked 
differences. Compare the measurements given above with those of tchelichofi (HW 0-74-0-82, CI 82-86, 
SI 95-100). Also the eyes of tchelichofi tend to be somewhat smaller, maximum diameter 0-20-0-23 x 
HW, and the dorsal alitrunk is more evenly and more strongly sculptured than in excelsior. 
Material examined 

South Africa: Cape Prov., Matroosberg (R. W. Tucker); Hermanus (Lockee-Bayne). 

Monomorium fridae Forel stat. n. 

Monomorium medinae r. fridae Forel, 1905: 183. Holotype worker, South Africa: Cape Prov., Willow- 
more (H. Brauns) (MHN) [examined]. 

Worker. TL 3-1-3-2, HL 0-84-0-85, HW 0-67-0-68, CI 80-81, SL 0-68-0-70, SI 101-103, PW 0-40-0-42, 
AL 0-90-0-93 (3 measured). 

Anterior margin of median portion of clypeus evenly concave. Sides of head notably convex in full-face 
view, the eyes situated at the widest point. Maximum diameter of eye 0-20-0-22 x HW, with 9 ommatidia 
in the longest row. Occipital margin of head very shallowly concave. With alitrunk in profile the 
promesonotal dorsum evenly convex, sloping posteriorly to the very feebly marked and scarcely impressed 
metanotal groove . Dorsum of propodeum flattened but not obviously concave , the dorsal surface rounding 
into the sides without distinct lateral marginations or carinae. Nodes of petiole and postpetiole in dorsal 
view both transversely elliptical, broader than long. Cephalic dorsum with 3-4 pairs of hairs which straddle 
the midline behind the level of the frontal lobes; without standing hairs at the occipital corners. Dorsal 
alitrunk without standing hairs. Petiole node with one pair and postpetiole with 1-2 pairs of backward 
directed hairs. First gastral tergite with numerous hairs in front of the apical transverse row, these hairs 
widely separated but distributed more or less evenly over the sclerite. Dorsum of head shining, unsculp- 
tured except for a fine faint superficial reticular patterning everywhere. Promesonotal dorsum sculptured 
as head but the patterning usually more strongly marked, especially on the posterior portion of the 
mesonotum. Propodeal dorsum shallowly and weakly punctulate-granular. First gastral tergite shining, 
with faint superficial reticulate patterning. Colour uniform brown, the gaster the same colour as, or slightly 
darker than, the alitrunk. 

M. fridae is given new status here as a valid species, reflecting the fact that it is not closely related to the 
Canary Island species medinae, a very specialized form known only from those islands. The real affinities of 



SOLENOPSIS GENUS-GROUP 345 

fridae lie within the tchelichofi-comp\ex and indeed fridae may be a senior synonym of tchelichofi itself. The 
two are remarkably similar in all respects except for size, fridae being a slightly smaller species with a 
fractionally narrower head and marginally longer scapes. Both share the same type-locality. Because of 
shortage of material referable to either name I have opted to keep them as separate species for the time 
being, but I strongly suspect that the acquisition of further samples will show fridae and tchelichofi to be 
synonymous by bridging the slight size gap shown in presently available material. 

Material examined 
South Africa: Cape Prov., Willowmore (H. Brauns); Doom Riv. (T. D. A. Cockerel!). 

Monomorium herero Forel stat. n. 

Monomorium salomonis subsp. herero Forel, 1910c: 16. Syntype workers, female, Namibia: Possession I. , 
v.1903 (L. Schultze) (MHN; BMNH) [examined]. 

Worker. TL 2-8-3-1, HL 0-70-0-78, HW 0-58-0-64, CI 78-83, SL 0-57-0-64, SI 99-100, PW 0-34-0-40, 
AL 0-80-0-90 (7 measured). 

Median portion of clypeus with its anterior free margin transverse, not concave or indented. Maximum 
diameter of eye 0-24-0-26 x HW and with 10-11 ommatidia in the longest row. Sides of head evenly 
convex in full-face view, the occipital margin shallowly concave. Metanotal groove not or only very feebly 
impressed. Propodeal dorsum with a flattened triangular area, not concave, lacking sharp margins or rims 
to the triangular area. Dorsum of head with 2-3 pairs of standing hairs behind the level of the frontal lobes 
and with another pair situated close to the occipital corners. Dorsal alitrunk without standing hairs. Petiole 
with a single pair and postpetiole with 1-2 pairs of backward directed hairs. First gastral tergite with 2 pairs 
of hairs present in front of the apical transverse row, situated at approximately one-third and one-half of 
the length of the sclerite. Dorsum of head sculptured with reticulation only. Promesonotal dorsum 
reticulate anteriorly, the sculpture becoming stronger posteriorly and approaching the reticulate-punctate 
condition of the propodeal dorsum. First gastral tergite with faint superficial reticulate patterning only, 
shining. Sides of pronotum finely reticulate, remainder of sides of alitrunk reticulate-punctate. Colour 
uniform dark brown. 

Known only from the syntypic series collected on Possession Island off the coast of Namibia, herero 
remains an enigmatic species. It appears to be related to the South African willowmorense and the 
Namibian kitectum, but in both of these the cephalic sculpture is vestigial. Besides this kitectum is smaller 
than herero and has relatively larger eyes (HW 0-43-0-45, maximum diameter of eye 0-29-0-31 x HW), 
and willowmorense has decidedly shorter scapes (SI 88-93). In overall appearance herero approaches 
subopacum, but has the head much less strongly sculptured and lacks the median clypeal notch or 
impression characteristic of the latter. 

Material examined 
Namibia: Possession I. (L. Schultze). 

Monomorium hirsutum Forel stat. n. 

Monomorium bicolor subsp. hirsutum Forel, 1910J: 251. Syntype workers, Ethiopia: Nefassit (K. 
Escherich) (MHN; BMNH) [examined]. 

Worker. TL 3-2-3-4, HL 0-76-0-82, HW 0-62-0-67, CI 81-83, SL 0-62-0-68, SI 99-103, PW 0-40-0-44, 
AL 0-90-1-00 (6 measured). 

Prominent median portion of clypeus with its anterior margin shallowly concave. Eyes smaller than in 
any other member of the bicolo r-complex, the maximum diameter 0-19-0-21 x HW and with 9-10 
ommatidia in the longest row. Petiole and postpetiole nodes about equal in width in dorsal view (ca 
0-20-0-22), each distinctly transverse, anteroposteriorly compressed and broader than long. Propodeal 
dorsum slightly longitudinally impressed medially but lacking lateral carinae or marginations. Dorsum of 
head, entirety of alitrunk, petiole and postpetiole, all evenly densely reticulate-punctate, the punctures 
small, very crowded and all sharply defined. First gastral tergite shagreenate, the sculpture densest basally 
and fading apically. Dorsal surfaces of head, promesonotum, propodeum, petiole, postpetiole and gaster 
all with numerous fine standing hairs which are erect to subdecumbent and very dense; the propodeal 
dorsum with 5-6 pairs of hairs. Occipital margin of head in full-face view with projecting hairs across its 
entire width. Sides of head behind eyes with 1-2 pairs of projecting hairs in front of each occipital corner 



346 B. BOLTON 

which are closer to the corner than to the eye. Head, alitrunk, petiole and postpetiole orange-yellow to 
orange-red, the gaster blackish brown to black. 

Known only from the type-series, hirsutum has been treated to the present as a subspecies of bicolor. It 
is, however, conspicuously densely hairy, in contrast to bicolor which lacks hairs on the dorsal alitrunk and 
has only sparse gastral pilosity. M. hirsutum also has shorter scapes and smaller eyes than bicolor, as 
follows. 

M. bicolor SI 104-115, maximum diameter of eye 0-24-0-27 x HW; 

M. hirsutum SI 99-103, maximum diameter of eye 0-19-0-21 x HW. 

The closest relative of hirsutum appears to be an unidentified species from South Yemen (in BMNH) 
which matches hirsutum in colour, pilosity and general appearance, but which has erect pubescence on the 
scapes, even smaller eyes, and a deeply impressed metanotal groove followed by a conspicuously convex 
propodeal dorsal outline. In hirsutum the metanotal groove is very shallow and the propodeal dorsum is 
more or less flat in profile, approximately continuing the line of the promesonotum. 

M. hirsutum is easily distinguished from all other Afrotropical members of the bicolor-comp\ex as it is 
the only species to have hairs present on the propodeum. Only one other species in the entire salomonis- 
group, as represented in sub-Saharan Africa, has the propodeum densely hairy, albopilosum, but this is 
quickly distinguished by the characters noted in the key. 

Material examined 
Ethiopia: Nefassit (K. Escherich). 

Monomorium ilgii Forel 

Monomorium ilgii Forel, 1894a: 84. Syntype workers, Ethiopia: 'Siidabessinien' (Ilg) (MHN; BMNH) 
[examined]. 

Worker. TL 2-7-3-1, HL 0-66-0-78, HW 0-51-0-60, CI 76-77, SL 0-52-0-62, SI 102-105, PW 0-34-0-38, 
AL 0-76-0-90 (3 measured). 

Anterior margin of median portion of clypeus shallowly concave. Eyes relatively large and very 
conspicuous, the maximum diameter 0-33 x HW and with 9-11 ommatidia in the longest row. Sides of 
head evenly shallowly convex in full-face view, the convexity more marked in larger than in smaller 
workers. Occipital margin broadly but shallowly concave. Promesonotum in profile flat to shallowly 
convex dorsally, the metanotal groove only extremely feebly impressed. Propodeal dorsum flat to 
shallowly concave between the lateral marginations. Petiole node high and narrow in profile; both nodes 
narrow from front to back and conspicuously transverse in dorsal view, much broader than long. Cephalic 
dorsum with 4-5 pairs of hairs straddling the midline behind the frontal lobes, and the occipital margin with 
another pair situated close to the corners. Pronotal dorsum with 2-3 pairs of standing hairs, and larger 
workers also with a pair on the mesonotum. Propodeal dorsum without standing hairs. Petiole node with 
one pair and postpetiole with 3 pairs of elongate hairs. First gastral tergite with numerous standing hairs 
which are more or less evenly distributed over the entire sclerite. Head smooth, unsculptured except for 
very faint superficial reticular patterning. Pronotal dorsum similar to head but mesonotum with more 
conspicuous but still superficial reticulation. Propodeal dorsum with weakly reticulate-granulate sculpture. 
Sides of alitrunk behind the glossy pronotum weakly reticulate to reticulate-granulate. First gastral tergite 
unsculptured or at most with vestigial reticulate patterning basally. Colour uniform yellow. 

This distinctive species keys out with excelsior and superficially the two appear to be closely related. For 
this reason I have included ilgii in the tchelichofi-complex, but I suspect that ilgii may have come to 
resemble excelsior convergently. Little more can be said at present as both are known only from their short 
type-series. 

Material examined 
Ethiopia: 'Siidabessinien' (Ilg). 

Monomorium junodi Forel stat. n. 

Monomorium salomonis subsp. junodi Forel, 19106: 441. Syntype workers, South Africa: Transvaal, 

Shiluvane (Junod) (MHN) [examined]. 
Monomorium delagoense var. pretoriensis Arnold, 1944: 15. Holotype female, paratype workers, South 

Africa: Pretoria, xii.1925 (/. C. Faure) (BMNH) [workers examined]. Syn. n. 



SOLENOPSIS GENUS-GROUP 347 

Worker. TL 2-8-3-6, HL 0-70-0-94, HW 0-56-0-80, CI 79-87, SL 0-52-0-70, SI 85-100, PW 0-38-0-50, 
AL 0-80-1 -02 (30 measured). 

Median portion of clypeus with anterior free margin shallowly concave. Eyes of moderate size, the 
maximum diameter 0-22-0-25 x HW, with 9-11 ommatidia in the longest row. Posteroventral occipital 
angles broadly and evenly rounded. Metanotal groove narrow and feebly impressed. Propodeal dorsum 
flat to shallowly concave longitudinally, the lateral margins of the propodeum often sharply defined, in 
some samples represented by a pair of carinae. In general the more concave the propodeal dorsum the 
more sharply defined are the lateral margins. Petiole node in dorsal view anteroposteriorly compressed, its 
dorsal surface narrow. Dorsum and sides of head, entire alitrunk, petiole and postpetiole sharply 
reticulate-punctate. First gastral tergite reticulate to shagreened. Area of head between and immediately 
behind the frontal lobes usually finely longitudinally striate. Dorsum of head with several pairs of standing 
hairs behind the level of the frontal lobes. Promesonotum dorsally with at least a single pair of hairs (at the 
pronotal humeri), more often with up to 5 or 6 pairs present. Propodeal dorsum hairless. Petiole with 1-2 
and postpetiole with 2-3 pairs of backward directed hairs. First gastral tergite with numerous standing 
hairs which are evenly distributed over the sclerite in front of the apical transverse row. Colour uniform 
medium to dark brown, often with the gaster darker in shade. 

Among the Afrotropical members of the salomonis-group nine species have standing hairs present on 
the dorsal alitrunk. They are found in junodi, hirsutum, albopilosum, excelsior, pharaonis, delagoense, 
vatranum, marshi, and some populations of rufulum. Alitrunk hairs maybe numerous or may be restricted 
to a single pair at the pronotal humeri. M. junodi is isolated from this assemblage by the characters 
discussed in the introduction to the salomonis-group and those indicated in the key to species. 

The distribution of junodi appears to be restricted to southern Africa, it having been recorded only from 
Botswana, Zimbabwe and South Africa, and its closest relative appears to be delagoense, from which it is 
separated by its much coarser sculpture. In junodi the cephalic dorsum is evenly blanketed with dense, 
sharply defined reticulate-punctate sculpture, as is the entire alitrunk both dorsally and laterally, so that 
the intensity of sculpture on the dorsal head and alitrunk is approximately the same. In delagoense the 
cephalic dorsum is finely shagreenate to superficially reticulate, the sculpture much effaced and con- 
spicuously less dense and intense than the sharply reticulate-punctate dorsal alitrunk. 

Four workers of junodi in the BMNH collection are labelled as types of M. afrum var. faurei Arnold 
[South Africa: Pretoria, Rosslyn, xii.1925 (J. C. Faure).] This is merely a manuscript name, never having 
been published by Arnold. The specimens in question bear no relationship to faurei Santschi ( = exiguum), 
from Gabon, nor should they be associated with afrum. The name occurs, however, in Samways (1983), as 
faurei Arnold; the correct identity of Samway's material is junodi. 

Material examined 

Botswana: Xani Pan (A Russell-Smith); Okavango Delta, Smiti (A. Russell-Smith); Shorobe (A. 
Russell-Smith); Serowe (P. Forchhammer). Zimbabwe: Bulawayo (G. Arnold); Umtali (G. Arnold); 
Bembesi (G. Arnold); Victoria Falls (G. Arnold); Victoria Falls (W. L. Brown); Harare (A. Watsham). 
South Africa: Transvaal, Shiluvane (Junod); Nelspruit (M. Samways); Pretoria (G. Arnold); Pretoria, 
Rosslyn (/. C. Faure). 

Monomorium ki tectum sp. n. 

(Fig. 49) 

Holotype worker. TL 2-3, HL 0-60, HW 0-45, CI 75, SL 0-46, SI 102, PW 0-30, AL 0-70. 

Anterior free margin of median portion of clypeus transverse to extremely feebly convex, not indented 
medially. Head in full-face view with sides very shallowly convex and occipital margin almost transverse, 
with only the shallowest degree of concavity. Eyes relatively large, the maximum diameter 0-31 x HWand 
with 9 ommatidia in the longest row. With the alitrunk in profile the promesonotal dorsal outline almost flat 
behind the anterior curvature and sloping shallowly to the metanotal groove; the latter almost unimpress- 
ed, making only the slightest of indentations in the outline. Dorsum of propodeum flattened but not 
impressed, the dorsum rounding narrowly into the sides but without margination. Petiole and postpetiole 
in dorsal view of approximately equal width , the latter only fractionally broader than the former. Petiole in 
profile with the node cuneate, very narrowly rounded dorsally. Subpetiolar process indistinct, forming a 
low inconspicuous flange which runs back almost to the level of the spiracle. In profile the cephalic dorsum 
with appressed sparse pubescence but without standing hairs behind the level of the frontal lobes. Ventral 
surface of head with some fine projecting hairs. Dorsal alitrunk without standing hairs. Petiole and 
postpetiole each with one pair of backward directed hairs. First gastral tergite with sparse appressed 
pubescence, lacking hairs except for a single pair at about the midlength and a transverse row at the apex of 



348 B. BOLTON 

the sclerite. Dorsum of head polished and shining, the surface with an extremely faint superficial reticular 
patterning only. Promesonotal dorsum reticulate anteriorly, the sculpture becoming denser posteriorly. 
Propodeal dorsum reticulate to feebly reticulate-shagreenate. Sides of pronotum superficially reticulate as 
head, remainder of alitrunk sides more strongly reticulate or reticulate-shagreenate. First gastral tergite 
very faintly superficially reticulate, shining. Colour brown, the head and gaster darker in shade than the 
alitrunk, petiole and postpetiole. 

Paratype workers. TL 2-2-2-3, HL 0-58-0-60, HW 0-43-0-45, CI 73-75, SL 0-44-0-46, SI 100-102, PW 
0-30-0-32, AL 0-68-0-70 (5 measured). As holotype but in two the first gastral tergite with another pair of 
hairs, sited between the base and the pair at the tergal midlength. In one paratype the alitrunk is almost as 
dark in colour as the head and gaster, and in another the subpetiolar process is slightly convex, forming a 
low elongate lobe rather than a straight-edged flange. Maximum diameter of eye 0-29-0-31 x HW, with 
8-9 ommatidia in the longest row. 

Holotype worker, Namibia: Namib Desert, 15° 36' E, 23° 04' S, sample P 22, pitfall, 1984 (A. C. Marsh) 
(BMNH). 
Paratypes. 5 workers with same data as holotype (BMNH; MCZ). 

A relatively small but conspicuous species closely related to willowmorense but separated from it by the 
numerous characters indicated in the key. 

Monomorium tnantazenum sp. n. 

Holotype worker. TL 2-7, HL 0-70, HW 0-53, CI 76, SL 0-62, SI 117, PW 0-34, AL 0-82. 

Anterior margin of median portion of clypeus with a very small median indentation. Head in full-face 
view with sides roughly parallel to slightly anteriorly divergent in front of the eyes, distinctly convergent 
posteriorly behind the eyes. Occipital margin concave medially. Eyes of moderate size, the maximum 
diameter 0-26 x HW and with 9 ommatidia in the longest row. Antennal scapes relatively long, SI > 115. 
Pronotal dorsum in profile convex anteriorly, the posterior portion of the pronotum and the mesonotum 
forming a single almost flat surface which slopes posteriorly. Metanotal groove not impressed, the 
propodeal dorsum on a lower level than the mesonotum. Propodeal dorsum flattened, the margins 
separating dorsum and sides very feebly delimited. Petiole node in profile small and low, bluntly cuneate in 
shape. Cephalic dorsum in holotype with only a single pair of standing hairs behind the level of the frontal 
lobes, this pair situated close to the occipital margin (the holotype is most probably slightly abraded, see 
under paratypes below). Dorsal alitrunk without standing hairs. Petiole and postpetiole each with one pair 
of backward directed hairs. First gastral tergite with hairs scattered but more or less evenly distributed over 
the sclerite in front of the apical transverse row. Dorsum of head roughly reticulate to reticulate-granulate 
everywhere. Pronotal dorsum reticulate, the edges of the reticulations becoming raised and more sharply 
defined posteriorly on the mesonotum; propodeum weakly reticulate-punctate dorsally. Sides of pronotum 
with superficial reticular patterning, remainder of sides of alitrunk reticulate to shallowly reticulate- 
punctate. First gastral tergite glossy, with superficial reticular patterning only. Colour black to blackish 
brown, the mandibles dull yellow. 

Paratype workers. TL 2-8-3-0, HL 0-74-0-80, HW 0-55-0-60, CI 74-77, SL 0-66-0-72, SI 117-122, PW 
0-34-0-39, AL 0-85-0-92 (9 measured). Maximum diameter of eye 0-26-0-28 x HW, with 9-10 ommatidia 
in the longest row. As holotype but dorsum of head with 2-3 pairs of hairs straddling the midline behind the 
level of the frontal lobes. Colour of mandibles varying from dull yellow to light brown. Petiole node 
dorsally more broadly rounded in some paratypes than in holotype. Body colour may be uniformly black or 
blackish brown, or the gaster may be a different shade to the head and alitrunk. The median indentation of 
the clypeus, feeble in the holotype, is absent in some paratypes. 

Holotype worker, Namibia: Namib Desert, 14° 51' E, 23° 01' S, pitfall, sample P 12, 1984 (A. C. Marsh) 
(BMNH). 

Paratypes. 2 workers with same data as holotype; 3 workers with same data but 14° 39' E, 22° 59' S, 
sample P 13; 4 workers, Namib Desert, Swartbank, 14° 50' E, 23° 16' S, sandy plain, 1.x. 1981, sample 174 
(A C. Marsh) (BMNH; MCZ). 

Non-paratypic material examined. Namibia: Skeleton Coast, Ugab River (S. Braine). This sample 
matches the type-series in all respects except for its colour, it being dark brown rather than blackish brown 
to black. 



SOLENOPSIS GENUS-GROUP 349 

Within the v/afor-complex mantazenum is differentiated by its relatively small eyes, uniformly dark 
colour and lack of hairs on the alitrunk. 

Monomorium marsh isp. n. 

(Figs 50, 53) 

Holotype worker. TL 31, HL 076, HW 0-54, CI 71, SL 0-68, SI 126, PW 0-38, AL 0-94. 

Anterior margin of median portion of clypeus shallowly convex. Head in full-face view with sides weakly 
divergent in front of eyes and weakly convergent behind them, the occipital margin broadly but shallowly 
concave. Maximum diameter of eye 0-30 x HW, with 12 ommatidia in the longest row. Head relatively 
long and narrow, scapes relatively very long (CI and SI, above). Alitrunk long and low in profile, with 
promesonotal dorsum evenly shallowly convex and sloping posteriorly to the unimpressed metanotal 
groove. Propodeal dorsum long and low, distinctly on a much lower level than the promesonotum. Node of 
petiole in profile small and quite low, the anterior peduncle of the petiole lacking a conspicuous 
anteroventral process, having instead merely a short very low ridge. Cephalic dorsum with 4-5 pairs of 
erect hairs straddling the midline behind the level of the frontal lobes, and with a transverse row of 6 
standing hairs along the occipital margin, the outermost of which is close to the occipital corner on each 
side. Pronotal and mesonotal dorsa both with standing hairs present, the hairs longer and denser on the 
former than on the latter. Propodeal dorsum without hairs. There is variation in distribution of pilosity, see 
paratype discussion below. Nodes of petiole and postpetiole each with 2 pairs of backward directed hairs. 
First gastral tergite with numerous but widely spread hairs present in front of the apical transverse row, the 
hairs more or less evenly distributed over the entire sclerite. Dorsum of head finely reticulate to 
reticulate-shagreenate. Dorsal alitrunk more sharply reticulate to finely reticulate-punctate everywhere. 
Sides of alitrunk reticulate-punctate except for the pronotum, which is less strongly sculptured. First 
gastral tergite with fine superficial reticulate patterning only. Head and alitrunk dull orange-brown, gaster 
black and glossy. 

Paratype workers. TL 2-7-3-2, HL 0-68-0-76, HW 0-47-0-55, CI 70-74, SL 0-62-0-68, SI 120-130, PW 
0-32-0-39, AL 0-80-0-98 (11 measured). Maximum diameter of eye 0-28-0-31 x HW, with 11-13 
ommatidia in the longest row. Variation in pilosity shows the head with 3-5 pairs straddling the midline 
behind the level of the frontal lobes; occipital margin with a transverse row of 4 or 6 hairs; pronotum with 
4-5 pairs of hairs; mesonotum with 0-2 pairs; propodeum usually hairless but with a single pair in one 
specimen; petiole node with 1-2 pairs; postpetiole with 2 pairs. Colour varies from light orange with a dark 
brown gaster, to dull orange-brown with a black gaster. 

Holotype worker, Namibia: Namib Desert, 15° 18' E, 23° 06' S, pitfall, sample P 11, 1984 (A. C. Marsh) 
(BMNH). 

Paratypes. 5 workers with same data as holotype; 3 workers with same data but 15° 36' E, 23° 04' S, 
sample P 10; 3 workers, Mirabeb, 8.iv.l982, sample M 12 (A. C. Marsh) (BMNH; MCZ). 

The long antennal scapes, distinctive colour pattern and presence of hairs on the dorsal alitrunk make 
this Namib Desert species immediately recognizable. Its closest relative within the v/afor-complex appears 
to be vatranum, but this is a uniformly darkly coloured species with shorter scapes, and its alitrunk pilosity 
is restricted to a single pair of hairs at the pronotal humeri. 

Monomorium mediocre Santschi 

Monomorium mediocre Santschi, 1920a: 376, fig. 13. Syntype workers, South Africa: Kimberley (G. 
Arnold) (BMNH) [examined]. 

Worker. TL 1-9-2-0, HL 0-50-0-54, HW 0-41-0-43, CI 80-84, SL 0-37-0-39, SI 90-93, PW 0-26-0-27, 
AL 0-54-0-56 (7 measured). 

Median portion of clypeus with the anterior margin transverse to shallowly convex. With the head in 
full-face view the sides more or less evenly shallowly convex and the occipital margin shallowly concave 
medially. Eyes at midlength of sides, the maximum diameter of the eye 0-21-0-24 x HW and with 6-8 
ommatidia in the longest row. Promesonotal dorsal outline convex in profile, sloping posteriorly to the 
metanotal groove which is feebly or not impressed. Dorsum of head without standing hairs behind level of 
the frontal lobes. Dorsal alitrunk without standing hairs. Petiole node lacking hairs but postpetiole with a 
single backward directed pair. First gastral tergite hairless except for the apical transverse row. Dorsum of 



350 B. BOLTON 

head with extremely faint superficial reticular patterning, which is almost effaced. Pronotum with 
superficial reticular patterning, which is almost effaced. Pronotum with superficial reticular patterning, the 
mesonotum posteriorly somewhat more strongly reticulate and the propodeum very finely granulate to 
weakly punctulate-shagreenate. First gastral tergite only superficially marked with faint reticular pattern- 
ing. Colour uniformly yellow to very light brown, frequently the gastral tergites behind the first darker in 
shade than the first. 

This small yellowish species with very reduced sculpture and pilosity appears to be closely related to the 
Namibian esharre and nirvanum. The last named is easiest distinguished by its retention of a pair of hairs on 
the petiole node, which is absent in the other two. M. mediocre and esharre are separated by their 
differences in cephalic index, eye size, and relative position of eyes which in esharre are slightly in front of 
the midlength of the sides. 

Material examined 

Zimbabwe: Umgusa Riv., Sawmills (G. Arnold); Igusi (G. Arnold). South Africa: Kimberley (G. 
Arnold). 

Monomorium micropacum sp. n. 

Holotype worker. TL 24, HL 0-62, HW 0-48, CI 77, SL 0-50, SI 104, PW 0-34, AL 0-70. 

Anterior free margin of median portion of clypeus concave. Maximum diameter of eye 0-21 x HW and 
with 8 ommatidia in the longest row. Sides of head feebly convex in full-face view and somewhat 
convergent posteriorly, so that the head is slightly narrower across the occipital corners than immediately 
behind the eyes. Dorsum of pronotum convex anteriorly but the posterior portion of the pronotum and the 
mesonotum more or less flat or even very shallowly concave in profile, sloping posteriorly to the distinctly 
impressed metanotal groove. Propodeal dorsum in profile more steeply sloping than the mesonotum, the 
dorsum and declivity meeting in a broadly rounded angle. Propodeal dorsum approximately flat trans- 
versely between the blunt, posteriorly divergent marginations which separate dorsum from sides. Peduncle 
of petiole with a very narrow strip-like ventral process. Dorsum of head with three pairs of standing hairs 
behind the level of the frontal lobes. Dorsal alitrunk without standing hairs; petiole with one pair, 
postpetiole with two pairs of hairs. First gastral tergite evenly pilose, with 10 or more pairs of hairs in front 
of the apical transverse row. Dorsum of head from level of posterior margins of eyes to occipital margin 
blanketed by fine and dense reticulate-punctate sculpture, the punctures all sharply defined and decreasing 
slightly in size posteriorly; without other sculpture on head except for a few very fine striae between the 
frontal lobes and spanning the cephalic midline immediately behind the frontal lobes. All dorsal and lateral 
surfaces of alitrunk finely and sharply densely reticulate-punctate. Petiole and postpetiole reticulate- 
punctate to reticulate-granulate, the sculpture not quite as sharply defined as on the alitrunk. First gastral 
tergite very finely and densely shagreenate basally, apically this sculpture reducing to fine superficial 
reticulation only. Colour a uniform dull light brown, the cephalic dorsum slightly darker in shade than the 
rest of the body. 

Paratope worker. TL 2-3, HL 0-61, HW 0-48, CI 79, SL 0-51, SI 106, PW 0-33, AL 0-68. As holotype but 
maximum diameter of eye 0-23 x HW, again with 8 ommatidia in the longest row. Colour darker brown 
than the holotype and more nearly the same shade everywhere , perhaps implying that the holotype had not 
achieved its full adult colouring. 

Holotype worker, South Africa: Natal, Umlalazi Nat. Res., 25.iii. 1979 (D. J. Brothers) (BMNH). 
Paratype. 1 worker with same data as holotype (BMNH). 

This South African species resembles a smaller version (compare measurements) of opacum and has a 
much more densely hairy gaster. Where opacum has only 1-2 pairs of hairs on the first tergite micropacum 
has about 10 in front of the apical transverse row. On the head micropacum has 3 pairs of standing hairs 
behind the level of the frontal lobes where opacum has none or at most one pair, close to the occipital 
margin. 

Monomorium minor Stitz stat. n. 

Monomorium salomonis var. minor Stitz, 1923: 156. Syntype workers, Namibia: Farm Neudamm, 
10-15. v. 1911 {Michaelsen); Kuibis, 15. vh. 1911 (Michaelsen) (not found in MNHU, presumed lost). 



SOLENOPSIS GENUS-GROUP 351 

Worker. TL 2-6-2-9, HL 0-68-0-70, HW 0-49-0-51 , CI 70-74, SL 0-54-0-58, SI 1 12-1 16, PW 0-34-0-37, 
AL 0-78-0-84 (8 measured). 

Median portion of clypeus with anterior margin transverse to very shallowly concave, sometimes with a 
minute notch medially. Maximum diameter of eye 0-28-0-30 x HW, and with 8-9 ommatidia in the 
longest row. Sides of head weakly convergent behind the eyes and the occipital margin shallowly concave 
medially in full-face view. Promesonotum shallowly convex in profile, the mesonotum sloping weakly to 
the very feebly impressed metanotal groove. Propodeal dorsum flattened to weakly impressed, the lateral 
margins bluntly indicated. Dorsum of head with 2 pairs of standing hairs present behind the level of the 
frontal lobes; the first pair situated just behind the level of the eyes, the second pair at the occipital margin. 
Dorsal alitrunk without standing hairs; the petiole with one pair and the postpetiole with two pairs of 
backward directed hairs. First gastral tergite with hairs evenly distributed over the sclerite in front of the 
apical transverse row. Cephalic dorsum opaque and with a roughened and silky appearance, the sculpture 
finely reticulate-shagreenate to punctulate-shagreenate, usually mid-dorsally with superimposed extreme- 
ly fine scratch-like longitudinal striolae. Dorsal alitrunk finely reticulate-shagreenate on pronotum, 
grading to feebly punctulate-shagreenate on the propodeum. Colour uniform dull yellow, often with the 
sides and posterior margin of the first gastral tergite, and the succeeding tergites, slightly darker. 

As far as can be ascertained no syntypes of this species remain in existence. The original description of 
minor is short and quite vague, saying merely, '2mm. Smaller than typical form [i.e. salomonis]. Head 
narrower; antennal scape overreaching occipital margin by its own thickness. Petiole node with peduncle 
somewhat shorter. Yellow with brownish tint, the gaster in some samples somewhat darkened.' 

I have not seen any Namibian specimens matching this description but a series from Porto Alexandre, in 
south-eastern Angola, fits fairly well and so I have applied the name minor to this series, as reflected in the 
diagnosis given above. 

Material examined 
Angola: Porto Alexandre (P. Hammond). 

Monomorium nirvanum sp. n. 

Holotype worker. TL 2-2, HL 0-58, HW 0-46, CI 79, SL 0-46, SI 100, PW 0-30, AL 0-62. 

Median portion of clypeus with its anterior margin transverse to very feebly convex. Head in full-face 
view with sides very shallowly convex and with the occipital margin broadly but extremely shallowly 
concave, almost transverse. Eyes at midlength of sides of head, the maximum diameter 0-26 x HW and 
with 10 ommatidia in the longest row. Alitrunk in profile with the promesonotal dorsum convex anteriorly 
and sloping posteriorly. The metanotal groove not impressed but the propodeal dorsum distinctly on a 
much lower level than the promesonotum. Cephalic dorsum without standing hairs behind the level of the 
frontal lobes. Dorsal alitrunk lacking standing hairs. Petiole node and postpetiole each with a single pair of 
backward directed hairs. First gastral tergite hairless except for the apical transverse row. Dorsum of head 
sculptured with very faint superficial reticular patterning only, the marking almost effaced. Pronotum with 
superficial reticular patterning, the sculpture becoming more conspicuous posteriorly though still very 
feeble. Propodeum weakly reticulate to granular. First gastral tergite with superficial reticular patterning 
only. Colour uniform light yellowish brown. 

Paratype worker. TL 21, HL 0-53, HW 0-43, CI 81, SL 0-41, SI 95, PW 0-26, AL 0-59. Maximum 
diameter of eye 0-28 x HW and with 9 ommatidia in the longest row. Otherwise as holotype. 

Holotype worker, Namibia: Namib Desert, 15° 19' E, 23° 43' S, dunes, sample V 2154, 2. hi. 1982 (5. 
Simleit) (BMNH). 
Paratype. 1 worker with same data as holotype (MCZ). 

A very distinctive small species of the salomonis-group as represented in sub-Saharan Africa, the 
Namibian nirvanum is characterized by its lack of pilosity on the first gastral tergite (apart from the apical 
transverse row) , its extremely reduced cephalic sculpture , the position of its eyes, and retention of a single 
pair of hairs on both the petiole and postpetiole whilst all standing hairs have been lost from the alitrunk 
and from the cephalic dorsum behind the frontal lobes. M. nirvanum falls into the mediocre-complex. 



352 B. BOLTON 

Monomorium ocellatum Arnold 

Monomorium (Xeromyrmex) salomonls st. ocellatum Arnold in Santschi, 1920a: 377. Syntype workers, 
females, South Africa: Cape Prov., Willowmore (H. Brauns, G. Arnold) (BMNH; NMB) [examined]. 
Monomorium ocellatum Arnold; Arnold, 1944: 14. [Raised to species.] 

Worker. TL 3-1-3-7, HL 0-76-0-86, HW 0-60-0-69, CI 77-82, SL 0-60-0-70, SI 100-103, PW 0-43-0-48, 
AL 0-92-1-06 (8 measured). 

Anterior free margin of median portion of clypeus approximately transverse to concave. Eyes of 
moderate size, the maximum diameter 0-25-0-27 x HW and with 10-11 ommatidia in the longest row. 
Several workers in the type-series with a conspicuously developed median ocellus, but in others this is very 
small and in a few is vestigial. In general the ocellus is largest in large workers, but the variation seen in the 
type-series suggests that specimens lacking the ocellus may be found. Occipital margin of head conspi- 
cuously indented in full-face view. Promesonotum convex in profile, the highest point of the outline being 
at the junction of pro- and mesonotum, behind which the mesonotum slopes downwards to the narrowly 
impressed metanotal groove. Propodeal dorsum flattened and shallowly transversely concave. Dorsum of 
head in profile with about 5 pairs of standing fine hairs behind the level of the frontal lobes. In fresh 
specimens more may be present, but all the syntypes show signs of abrasion. Dorsal alitrunk without 
standing hairs. Petiole with 1-2 and postpetiole with 2-3 pairs of fine backward directed hairs. First gastral 
tergite with fairly dense fine pilosity on the basal third, the least abraded specimens showing about 6 pairs in 
this area. An apical transverse row of hairs is present on the first tergite. The area between the transverse 
row and the basal cluster of hairs shows one or two hairs in a few syntypes and it is probable that several may 
be present in fresh specimens; all the syntypes, however, show marked abrasion in this area. Dorsum of 
head opaque, blanketed by extremely fine dense sculpture which is reticulate-shagreenate to densely silkily 
striolate-granular. Promesonotal dorsum similarly sculptured but with fine dense reticulate ground- 
sculpture showing through. Propodeal dorsum anteriorly as promesonotum but posteriorly becoming 
more obviously reticulate to reticulate-punctate. First gastral tergite superficially reticulate. Colour 
brown, the gaster distinctly darker than the alitrunk. 

M. ocellatum is known only from the syntype series. It is closely related to subopacum but shows denser 
pilosity and finer sculpture than that species. The presence of a median ocellus in most of the worker 
syntypes should not be overstressed as a diagnostic feature because of its variable development even in the 
few workers available. 
Material examined 

South Africa: Cape Prov., Willowmore (H. Brauns). 

Monomorium opaciorsp. n. 

Monomorium salomonls r . junodi var . opacior Forel, 19136: 136. Syntype workers, Zimbabwe: Bulawayo, 
3.xi.l912, no. 130 (G. Arnold) (BMNH; MHN) [examined]. [Unavailable name.] 

Monomorium (Xeromyrmex) delagoense st. junodi var. serenum Santschi, 1928: 192. Syntype worker, 
male, Zimbabwe: Bulawayo, 26. xi. 1914 (G. Arnold) (NMB) [examined]. [Unavailable name.] 

Syntype workers. TL 2-2-2-4, HL 0-60-0-66, HW 0-47-0-50, CI 75-78, SL 0-48-0-52, SI 100-108, PW 
0-32-0-34, AL 0-68-0-74 (6 measured). 

Median portion of clypeus with anterior margin transverse, sometimes appearing very slightly convex. 
Sides of head in full-face view almost straight, only extremely feebly convex and somewhat convergent 
posteriorly. Occipital margin very shallowly concave. Eyes slightly in front of the midlength of the sides of 
the head, the maximum eye diameter 0-24-0-26 x HW, with 8-9 ommatidia in the longest row. Metanotal 
groove very feebly impressed. Dorsum of head with two pairs of standing hairs behind the level of the 
frontal lobes, the first situated just behind the level of the eyes, the second at the occipital margin. Dorsal 
alitrunk without standing hairs. Petiole node without hairs, the postpetiole with a single pair which projects 
backward. First gastral tergite with 1-2 pairs of hairs in front of the apical transverse row, situated on the 
basal half of the sclerite. Dorsum of head opaque, blanketed by fine and dense reticulate-shagreenate to 
punctate-shagreenate sculpture; mid-dorsally the sculpture with very fine dense longitudinal scratch-like 
striolae, giving the surface in this area a silky appearance. Pronotal dorsum finely reticulate to reticulate- 
shagreenate; posteriorly on the dorsal alitrunk the sculpture becoming more sharply reticulate or even 
weakly reticulate-punctate. First gastral tergite with superficial reticular patterning at least near the base, 
but this may fade out apically, leaving the sclerite featureless. Colour dull light brown, the gaster much 
darker brown and shining. 



SOLENOPSIS GENUS-GROUP 353 

Syntypes, 10 workers, Zimbabwe: Bulawayo, 3.xi.l912, no. 130 (G. Arnold) (BMNH; MHN). 
Non-syntypic material examined. Zimbabwe: 4 short series, Bulawayo (G. Arnold). Botswana: Okavan- 
go Delta, Shorobe (A. Russel-Smith). South Africa: Transvaal, Nelspruit {M. Samways). 

Dimensions of non-paratypic material. TL 2-3-2-7, HL 0-56-0-68, HW 0-43-0-52, CI 74-78, SL 
0-44-0-57, SI 102-110, PW 0-30-0-35, AL 0-64-0-80 (8 measured). Maximum diameter of eye 0-25-0-27 
x HW and with 8-9 ommatidia in the longest row. As syntypes but in some the first gastral tergite with 3 
pairs of hairs on the basal half. Development of fine striolate component of cephalic sculpture is variable; in 
some individuals it is conspicuous, in others virtually absent. Also variable is the extent of the superficial 
reticular patterning on the first gastral tergite and the colour, which ranges from dull yellowish brown to 
pale medium brown. The gaster is sometimes only marginally darker than the head and alitrunk in shade. 

The species is described from a syntypic series as Arnold's original series are mounted flat on card and all 
individuals have suffered some damage and abrasion. For this reason it has not proved possible to select a 
holotype from the original material which exhibits all the diagnostics of the species. 

Monomorium opacum Forel 

Monomorium opacum Forel, 1913a: 333. Syntype workers, Zaire: Katanga ( = Shaba), Shinsenda, 
10. vi. 1912 (Bequaert) (MHN; MRAC) [examined]. 

Worker. TL 3-3-3-5, HL. 0-80-0-86, HW 0-64-0-72, CI 80-86, SL 0-60-0-68, SI 90-100, PW 0-42-0-46, 
AL 0-96-1-04 (12 measured). 

Anterior free margin of median portion of clypeus transverse to shallowly convex. Maximum diameter 
of eye 0-22-0-25 x HW, with 10-11 ommatidia in the longest row. Metanotal groove only shallowly 
indented. Dorsum of propodeum flattened or shallowly concave, the posteriorly divergent lateral margins 
of the propodeum sometimes bluntly angular. Petiole bluntly conical in profile; in dorsal view the node 
somewhat broader than long and approximately the same width as the postpetiole. Dorsum and sides of 
head, entirety of alitrunk, petiole and postpetiole sharply densely reticulate-punctate everywhere. First 
gastral tergite finely shagreenate. Dorsum of head behind level of frontal lobes hairless or with a single pair 
close to the occipital margin. Dorsal alitrunk lacking hairs. Petiole with one pair and postpetiole with 1-2 
pairs of backward directed hairs. First gastral tergite with 1 -2 pairs of hairs in front of the apical transverse 
row. If only one pair present it is at the midlength of the tergite ; when a second pair also occurs it is usually 
between the base and the midlength of the tergite. Colour uniform medium to dark brown, the gaster 
usually darker in shade than the head and alitrunk. 

M. opacum is characterized by its dense, sharply defined reticulate-punctate sculpture, sparse pilosity 
and dark colour. It is most closely related to subdentatum from which it is only weakly separated (see 
below), and to micropacum which has about 10 pairs of hairs on the first gastral tergite and is noticeably 
smaller (HW 0-48, SL 0-50-0-51, PW 0-33-0-34). 

Material examined 

Uganda: Mbarara (R. M. C. Williams). Zambia: Mumbwa (Dollman); Mwengwa (Dollman). Zaire: 
Shaba, Shinsenda (Bequaert). Angola: Kanfuchi (T. D. A. Cockerell). Zimbabwe: Lupone (G. Arnold); 
Khami (G. Arnold); Nantwich (G. Arnold); Matopo Hills ( W. L. Brown). 

Monomorium ophthalmicum Forel 

Monomorium ophthalmicum Forel, 1894a: 87. Holotype worker, Ethiopia: 'Siidabessinien' (Ilg) (MHN) 
[examined]. 

Worker. TL 2-3, HL 0-62, HW 0-49, CI 79, SL 0-45, SI 92, PW 0-30, AL 0-68 (measurements of head 
approximate as holotype worker head is crushed). 

Anterior clypeal margin with its prominent median section extremely shallowly concave centrally. 
Dorsum of head crushed but sides apparently evenly shallowly convex and converging behind the eyes. 
Eyes large, the maximum diameter 0-35 x HW and with 10 ommatidia in the longest row. Promesonotum 
in profile shallowly convex, the highest point approximately at the midlength. Extreme posterior portion of 
mesonotal outline sharply downcurved to the metanotal groove but the latter not impressed. Propodeal 
dorsum extremely feebly concave, almost flat in outline. In dorsal view the posterior half of the propodeal 
dorsum very shallowly transversely concave. Petiole node in profile narrowly but bluntly subconical. 
Dorsum of head with very faint reticular patterning only, which becomes more distinct towards the 



HW 


SI 


eye 


0-50-0-60 


88-93 


0-24-0-26 x HW 


0-49 


92 


0-35 x HW 


0-43-0-45 


100-102 


0-29-0-31 x HW 



354 B. BOLTON 

occipital margin. Pronotal dorsum and sides finely reticulate-shagreenate, the mesonotal dorsum similarly 
but more strongly sculptured. Propodeal dorsum and sides of alitrunk behind the pronotum densely finely 
reticulate to reticulate-punctate. First gastral tergite very finely shagreenate at extreme base, this fading 
out posteriorly to fine superficial reticular patterning. Dorsum of head without standing hairs behind the 
level of the frontal lobes. Dorsal alitrunk without standing hairs. Petiole and postpetiole each with a single 
pair of backward directed hairs. First gastral tergite with a single pair of elongate hairs, situated 
approximately at the midlength. Colour uniform medium brown, the legs and antennae dull yellow. 

Known only from the damaged holotype, this Ethiopian species appears to belong to the subopacum- 
complex. In the key it runs out close to the southern African species kitectum and willowmorense but has 
different critical dimensions, as follows. 

willowmorense 
ophthalmicum 
kitectum 

Apart from this willowmorense workers have 2-3 pairs of hairs on the first gastral tergite in front of the 
apical transverse row, whereas kitectum and ophthalmicum have only a single pair; and ophthalmicum 
shows 10 ommatidia in the longest ocular row, a count only equalled by the largest workers of 
willowmorense. 

Material examined 

Ethiopia: 'Siidabessinien' (Ilg). 

Monomorium orangiae Arnold 

Monomorium (Xeromyrmex) orangiae Arnold, 1956: 67, figs 16, 16a. Paratype workers, South Africa: 
Orange River, Kakamas, 3.xii.l953 (R. H. N. Smithers) (BMNH) [examined]. 

Worker. TL 3-7-4-0, HL 0-92-0-98, HW 0-76-0-80, CI 81-83, SL 0-78-0-79, SI 98-102, PW 0-44-0-48, 
AL 1-02-1-06 (3 measured). 

Anterior margin of median portion of clypeus broadly and evenly concave. With the head in full-face 
view the sides evenly convex, broadest at the midlength and converging anteriorly and posteriorly. 
Maximum diameter of eye 0-21-0-22 x HW and with 10-12 ommatidia in the longest row, the eyes 
appearing small on the sides of the relatively massive broad head. Outline of promesonotum in profile 
shallowly convex, the mesonotum sloping posteriorly to the distinctly impressed metanotal groove. 
Propodeum flat to shallowly transversely concave dorsally, the dorsum separated from the sides by 
conspicuous narrowly rounded margins. Petiole node cuneate in profile, narrowly rounded dorsally. In 
dorsal view both nodes narrow and strongly transverse, much broader than long. Cephalic dorsum with 2-3 
pairs of hairs straddling the midline behind the level of the frontal lobes; without hairs close to the occipital 
corners. Dorsal alitrunk without standing hairs. Petiole with one pair and postpetiole with 1-2 pairs of 
backward directed hairs. First gastral tergite with 2-3 pairs of hairs in front of the apical transverse row. 
Head smooth, unsculptured except for vestigial superficial reticular patterning; promesonotal dorsum 
similarly sculptured. Propodeal dorsum with very feeble reticulate-shagreenate sculpture or only vestigial- 
ly shagreenate. Node of postpetiole unsculptured dorsally, the first gastral tergite unsculptured or with fine 
superficial reticular patterning. Colour uniform glossy dark brown. 

Very close to tchelichofi, orangiae is separated by its feebler alitrunk sculpture, unsculptured postpetiole 
node and more sharply defined lateral propodeal margins. 

Material examined 
South Africa: Orange River, Kakamas (R. H. N. Smithers). 

Monomorium osiridis Santschi 

Monomorium osiridis Santschi, 1915: 258, fig. 7. Holotype worker, Kenya: Bura, 1050 m, hi. 1912, st. no. 
61 (Alluaud & Jeannel) (NMB) [examined]. 

Worker. TL 1-7-1-9, HL 0-46-0-48, HW 0-34-0-38, CI 74-79, SL 0-32-0-34, SI 90-94, PW 0-22-0-24, 
AL 0-46-0-50 (6 measured). 



SOLENOPSIS GENUS-GROUP 355 

Anterior margin of median portion of clypeus shallowly concave. With head in full-face view the eyes 
distinctly in front of the midlength of the sides and the antennal scapes, when laid straight back, failing to 
reach the occipital margin. Maximum diameter of eye 0-21-0-24 x HW and with 6-7 ommatidia in the 
longest row. Sides of head very shallowly convex and weakly convergent posteriorly behind the level of the 
eyes. Ocipital margin very shallowly concave. Metanotal groove represented by a transverse line across 
the dorsum; in profile the metanotal groove not impressed. Dorsum of head lacking standing hairs. Dorsal 
alitrunk without standing hairs. Petiole and postpetiole without backward directed hairs. First gastral 
tergite without hairs, lacking even the apical transverse row. Apical transverse row of hairs present on the 
second and third gastral tergites . Mandibular sculpture very feeble , effaced on the apical half of each blade . 
Cephalic dorsum finely shagreenate between inconspicuous shallow pits. A mid-dorsal longitudinal strip, 
leading back from the clypeus, is unsculptured and shining. Dorsal alitrunk reticulate-shagreenate 
anteriorly, the sculpture bcoming stronger posteriorly on the promesonotum; propodeal dorsum finely 
reticulate-punctate. Sides of alitrunk finely reticulate to weakly reticulate-punctate, with a smooth patch 
low down on the side of the pronotum. Petiole and postpetiole finely reticulate to granulate. First gastral 
tergite very weakly shagreenate basally, but this fades out posteriorly leaving the sclerite smooth and 
shining. Colour uniform dull yellow. 

This small species is closely related to zulu and rabirium from southern Africa but tends to have slightly 
smaller eyes and is more strongly sculptured on the head. The fine but dense shagreenate sculpture seen on 
the head of osiridis contrasts strongly with the almost unsculptured appearance of zulu and rabirium, 
where the head retains only the faintest vestiges of superficial reticular patterning, or is smooth. Otherwise 
they are very similar, sharing the characters of veiy reduced pilosity, anteriorly shifted eyes and a lower 
palp formula (PF 1,2) than is usual in the salomonis-group (PF 2,2). 

Material examined 
Kenya: Bura (Alluaud & Jeannel); Tana Riv. , Kora (Collins & Ritchie). 

Monomorium parvinode Forel stat. n. 

Monomorium salomonis var . parvinode Forel, 1894a: 88. Holotype worker, Ethiopia: Sudabessinien' (Ilg) 
(MHN) [examined]. 

Worker. TL 2-2, HL 0-60, HW 0-47, CI 78, SL 0-44, SI 94, PW 0-30, AL 0-68. 

Median portion of anterior clypeal margin more or less transverse. Sides of head very weakly convex and 
feebly convergent behind the eyes. Maximum diameter of eye 0-30 x HW and with 10 ommatidia in the 
longest row. Metanotal groove feebly impressed. Dorsum of head with 2 pairs of standing hairs behind the 
level of the frontal lobes, the first situated just behind the level of the eyes and the second at the occipital 
margin. Dorsal alitrunk without standing hairs. Petiole node with one pair, and postpetiole with two pairs 
of backward directed hairs. First gastral tergite with several pairs of standing hairs on the basal half, the 
apical half of the sclerite hairless except for the apical transverse row. Cephalic dorsum opaque, blanketed 
by fine dense sculpture which is reticulate-shagreenate to punctulate-shagreenate ; the mid-dorsal area with 
minute and very fine longitudinal patterning so that the entire head has a silky appearance. Dorsal alitrunk 
finely and densely reticulate to reticulate-punctate. First gastral tergite finely shagreenate, the shagreening 
feebler apically than basally. Head and alitrunk medium yellowish brown, the gaster much darker brown. 

Only known from the holotype worker from southern Ethiopia, a short series from Sudan, and two 
workers from Harar, Ethiopia, which are tentatively associated here, parvinode appears closely related to 
the Ethiopian carbo, the Senegalese dakarense, and the southern African species opacior and minor, all of 
which share the same very characteristic cephalic sculpture and similar arrangement of standing pilosity. 

The Sudan material noted below matches the holotype well in most respects but has a somewhat larger 
petiole node and smaller eyes. Similarly, the two workers from Harar (MCZ) match the Sudanese 
specimens and show the same differences from the holotype. 

Given the paucity of material I have decided to include these short series under parvinode until some 
idea of variation in these characters can be ascertained. 

Material examined 
Ethiopia: 'Siidabessinien' (Ilg); Harar (Ilg). Sudan: Blue Nile, near Hilaliya (C. Sweeney). 



356 B. BOLTON 

Monomorium personation Santschi stat. n. 

Monomorium (Xeromyrmex) bicolor st. personatum Santschi, 1937: 220, fig. 29. Syntype workers, 

Angola: Kamba, 1932-33, no. 122 (A. Monard) (NMB) [examined]. 
Monomorium (Xeromyrmex) bicolor st. personatum var. bimaculatum Santschi, 1937: 221. Syntype 

workers, Angola: Mupa, 1932-33, no. 132 (A. Monard) (NMB) [examined]. [Unavailable name.] 
Monomorium bicolor st. personatum var. bimaculatoides Ettershank, 1966: 87. [Unnecessary replacement 

name for bimaculatum Santschi; unavailable name.] 

Worker. TL 3-0-3-5, HL 0-72-0-78, HW 0-52-0-58, CI 72-76, SL 0-58-0-66, SI 109-114, PW 0-37-0-42, 
AL 0-88-0-98 (7 measured). 

Basal (fourth) tooth of mandible only slightly smaller than the third tooth. Eyes relatively large, 
maximum diameter 0-31-0-33 x HW and with 10-1 lommatidia in the longest row. Head, alitrunk, petiole 
and postpetiole reticulate-punctate. First gastral tergite reticulate to shagreenate basally. With head in 
full-face view the sides lacking projecting hairs. Dorsal alitrunk without standing hairs; petiole with a single 
pair of hairs; postpetiole with two pairs. First gastral tergite with numerous standing hairs which are evenly 
distributed over the sclerite in front of the apical transverse row. Colour orange with blackish brown gaster, 
the two strongly contrasting. Base of first gastral tergite with a pair of yellow-orange spots of vaying size, 
one spot on each side of the midline. 

M. personatum is distinguished from all other members of the bicolor-complex by its relatively large 
eyes, the maximum diameter of 0-3 1-0-33 x HW contrasting with the combined range of 0-19-0-27 x HW 
shown in the remainder of the complex (bicolor, dictator, hirsutum, rufulum, westi). 

The dense gastral pilosity shown by personatum, as well as its large eyes, differentiates it from bicolor, 
the species with which it was originally associated as a subspecies. 

Material examined 

Angola: Kamba (A. Monard); Mupa (A. Monard). 

Monomorium pharaonis (L.) 

(Figs 24, 56, 60) 

Formica pharaonis L., 1758: 580. Syntype workers, Egypt (EUU) [not seen]. 

Formica antiguensis F., 1793: 357. Material not specified, West Indies: Antigua I. [not seen]. [Synonymy 

by Roger, 1862ft: 294; Mayr, 1862: 752.] 
Myrmica domestica Shuckard, 1838: 627. Syntype workers, female, Great Britain: London (Bostock) (no 

types known to exist). [Synonymy by Roger, 1862ft: 294; Mayr, 1862: 752.] (See note 1, below.) 
Atta minuta Jerdon, 1851: 105. Syntype workers, India (no types known to exist). [Synonymy by Emery, 

1892: 165.] 
Myrmica vastator Smith, 1857: 71. Syntype workers, Singapore (Wallace) (UM) [examined]. [Synonymy 

by Donisthorpe, 1932:449.] (See note 2, below.) 
Myrmica fragilis Smith, 1858: 124. Syntype workers, Singapore (Wallace) (BMNH) [examined]. 

[Synonymy by Mayr, 1886: 359.] 
Myrmica contigua Smith, 1858: 125. Holotype female, Sri Lanka (BMNH) [examined]. [Synonymy by 

Mayr, 1886: 359.] 
Monomorium pharaonis (L.) Mayr, 1862: 752. 

Note 1. 'Myrmica unifasciata Bostock, 1839.' This name appears as a junior synonym of pharaonis in the 
catalogues of Dalla Torre (1893), Wheeler (1922), and Emery (1922), but is not found in earlier indexes 
such as Mayr (1863) and Roger (1863ft). The reference given in the later catalogues to Bostock, 1839 [recte 
1838], is merely Bostock's account of ants invading his home; the offending species is not named in the 
short article. However, later in the same volume, under Journal of Proceedings (pp. li-lii), and in Shuckard 
(1838), it becomes apparent that Shuckard had seen Bostock's nuisance species and had initially suggested 
that it may be Myrmica unifasciata Latreille (a species now in Leptothorax) , but had later changed his mind 
and decided that the species in question was undescribed. He went on to describe them as Myrmica 
domestica Shuckard (1838). Thus there is not, and never has been, a Myrmica unifasciata Bostock, and the 
entries listed in the catalogues mentioned above are in error. 

Note 2. Myrmica vastator Smith was wrongly synonymized with M. destructor by Forel (1894a: 86), 
probably because he had seen some old destructor specimens in the BMNH collection which are 



SOLENOPSIS GENUS-GROUP 357 

misidentified as vastator by Smith . The syntypes of vastator which are housed at UM are junior synonyms of 
pharaonis, as Donisthorpe (1932) correctly pointed out. 

Worker. TL 2-2-2-4, HL 0-52-0-62, HW 0-40-0-48, CI 73-80, SL 0-44-0-52, SI 105-117, PW 0-26-0-30, 
AL 0-60-0-68 (50 measured). 

Mandibles weakly longitudinally rugulose, the rugular area frequently overlaid by a fine shagreening; 
sculpture usually absent on the apical portion of the mandibles close to the teeth, on the portion of the 
blade which is overlapped by the opposite mandible at full closure. Median portion of clypeus with its 
anterior margin shallowly concave. In full-face view the sides of the head evenly but very shallowly convex, 
the occipital margin shallowly convex to approximately transverse. Eyes relatively small, the maximum 
diameter 0-18-0-21 x HW and with 5-7 (usually 6) ommatidia in the longest row; the eyes situated just in 
front of the midlength of the sides of the head. Promesonotum convex in profile. Posteriormost portion of 
the mesonotum sloping steeply to the metanotal groove, much more steeply sloping than the anterior 
portion. Metanotal groove impressed. Dorsum of head with 3-4 pairs of standing hairs straddling the 
midline behind the level of the frontal lobes. Occipital margin with another, more laterally placed, pair of 
hairs which are close to the curve of the occipital corner. Pronotum dorsally with a single pair of standing 
hairs, situated at the humeri. Mesonotum with a single pair of anteriorly situated standing hairs; very rarely 
with a second shorter pair situated farther back on the mesonotum. Propodeal dorsum usually hairless but 
sometimes with a single short pair present at about the midlength. Petiole node with 1-2 pairs, postpetiole 
with 2-3 pairs of backward directed hairs. First gastral tergite with numerous hairs which are more or less 
evenly distributed over the sclerite in front of the apical transverse row. Dorsum of head and entirety of 
alitrunk finely and densely reticulate-punctate, the punctures sometimes slightly reduced on the head, 
pronotum, or both, so that the area appears finely reticulate rather than reticulate-punctate. Mid-dorsum 
of head, at about the level of the eyes, sometimes with a feebly shagreenate patch. First gastral tergite with 
vestigial traces of superficial reticular patterning only, in some the sclerite featureless. Colour uniform pale 
yellow to light yellowish brown, sometimes with a weak reddish tint. Sides and posterior margin of first 
gastral tergite, and remaining tergites, usually darker than the disk of the first tergite. 

One of the world's best known, most widely distributed and most successful tramp-species, not only in 
the genus Monomorium but in the family Formicidae as a whole, pharaonis has been recorded as a major 
domestic pest for well over a century. Records as early as Bostock (1838) and Jerdon (1851) indicate its 
remarkable house-infesting propensities and its peculiar ability to nest in any available small cavity once 
inside a dwelling. 

The past few decades have seen an incredible increase in the range and population density of this species 
in the temperate zones of the world, corresponding to a large extent with the spread of high-density 
apartment blocks and central heating systems; the species can persist outdoors only under exceptional 
circumstances outside the tropics (Kohn & Vlcek, 1986) . A direct result of the ant so thrusting itself into the 
public notice has been a welter of papers investigating all aspects of its life-history, behaviour and control. 
It is impractical to present a full bibliography here, but all salient features of studies on pharaonis can be 
obtained from the following short bibliography, and the further references included in the publications 
cited. 

Earlier literature is summarized in Wheeler (1922), Smith (1934), and Peacock et al. (1950); the 
exhaustive list given in Krombein et al. (1979) should also be consulted. Introductory and general 
information is given in Sudd (1967), Wilson (1971) and Dumpert (1978). More specialized aspects of 
studies on pharaonis can be obtained from the following. 

Mass rearing and laboratory culture of colonies: Kretzschmar (1971); Buschinger & Petersen (1971); 
Berndt & Kremer (1980); Samsinak et al. (1984). 

Control techniques: Eichler & Kleinsorge (1973); Berndt & Nitschmann (1977); Rupes etal. (1983). 

Summary of pheromone studies: Czechowski (1979). 

Aspects of biology and ethology: Lauterer (1971); Petersen & Buschinger (1971a, 19716); Beatson 
(1972); Eichler & Kleinsorge (1972); Holldobler (1973); Petersen-Braun (1977, 1982); Berndt & 
Nitschmann (1979). 

An interesting series of papers describing the establishment, distribution, biology and attempted 
eradication of pharaonis in Poland is given in Wisniewski et al. (1971); Czajkowska (1979); Krzeminska 
etal. (1979). Distribution on a world-wide basis is indicated by the following. North America: Krombein 
etal. (1979). South America: Kempf (1972). Africa: Wheeler (1922). Pacific Islands: Wilson & Taylor 
(1967). 

For comments on the relatives and place of origin of pharaonis see the notes on the pharaonis-complex in 
the introduction to the Salomon w-group. 



358 B. BOLTON 

Material examined 

Afrotropical region. Ghana: Kibi (D. Leston); Mole Game Res. (/. C. Greig); Aburi (P. Room); Tafo 
(A. H. Strickland). Nigeria: Ibadan (A. Russel-Smith); Gambari (B. Bolton); Ile-Ife (/. T. Medler). 
Cameroun: Nkoemvon (D. Jackson); Victoria (B. Malkin). Sudan: Juba to Khartoum (H. W. Bedford). 
Kenya: Kabete (H. E. Box). Tanzania: Dar es Salaam (D. Griffiths); Zanzibar (E. S. Brown). Zimbabwe: 
Bulawayo (G. Arnold). Mozambique: Beira (G. Arnold). Angola: Benguela. 

Other regions. India: Calicut (A. P. Rosy). Sri Lanka: Mihintale (Stubbs & Chandler); Bibile (R. 
Winney); no loc. (T. B. Fletcher). Thailand: Nong Hoi (D. Jackson). Philippines: Leyte, Visca (C. K. 
Starr). Singapore: (A. R. Wallace). East Malaysia: Sarawak, Long Pala (V. Eastop); Sabah, Gn. Silam 
(R. Leakey); Tawau Quoin (M. J. Way). Indonesia: Sulawesi, nr Morowali (M. Brendell); Minahassa 
(A. H. G. Alston); Java, Bogor (A. H. G. Alston); Irian Jaya, Vogelkopf (L. E. Cheesman); Cyclops 
Mts (L. E. Cheesman). Papua New Guinea: Lae (R. W. Paine). Solomon Is: Guadalcanal (R. A. Lever); 
Guadalcanal (E. S. Brown); Three Sisters (R. A. Lever). New Hebrides: Malekula (L. E. Cheesman). 
Fiji Is: Suva (R. A. Lever). Australia: Darwin (G. F. Hill); Qld., Bundaberg (R. C. L. Perkins); 
Redlynch. Guiana: Blairmont (H. E. Box). Trinidad (no data). Mexico: Acapulco (Hoge). Greece: 
Crete (D. M. A. Bate); Salonika (/. Waterston). Great Britain: London (series by /. C. Deeming, 
N. V. Barton, B. Bolton, T. Smith, R. N. Hedges, K. Guichard, E. R. Goodliffe); Surrey, Coulsdon; 
Berkshire, Reading; Essex, Clacton (D. Harwood); Sussex, East Grinstead (P. B. Cornwell); Devon, 
Exeter (F. R. Rowley); Norfolk, Norwich (Corran); Yorkshire, Leeds (/. Curtis). 

Monomorium rabirium sp. n. 

Holotype worker. TL 1-7, HL 044, HW 0-33, CI 75, SL 0-32, SI 97, PW 0-22, AL 0-44. 

Anterior margin of median portion of clypeus approximately transverse, indented medially. With the 
head in full-face view the eyes conspicuously in front of the midlength of the sides. Antennal scapes when 
laid straight back from their insertions not reaching the occipital margin. Maximum diameter of eye 
0-27 x HW and with 7 ommatidia in the longest row. Sides of head shallowly convex, weakly converging 
posteriorly behind the level of the eyes. Occipital margin broadly and extremely shallowly concave. 
Promesonotal dorsum feebly convex in profile, sloping shallowly behind to the very weakly impressed 
metanotal groove. Dorsum of head without standing hairs behind the level of the frontal lobes. Alitrunk, 
petiole and postpetiole without hairs. First gastral tergite without standing hairs, even the apical transverse 
row of hairs which is almost universal in the salomonis-group is absent here. (Apical transverse rows of 
standing hairs are present on the second and third tergites.) Mandibular sculpture very feeble. Dorsum of 
head sculptured only with the last faint vestiges of superficial reticular patterning, almost entirely effaced. 
Pronotal dorsum faintly reticulate to feebly shagreenate, the mesonotum more obviously shagreenate and 
the propodeal dorsum finely reticulate-shagreenate. First gastral tergite faintly superficially shagreenate to 
smooth. Colour pale brownish yellow. 

Paratype workers. TL 1-7, HL 0-45-0-48, HW 0-34-0-36, CI 75-77, SL 0-32-0-34, SI 92-97, PW 
0-22-0-23, AL 0-46-0.48 (6 measured). Maximum diameter of eye 0-26-0-28 x HW and with 7-8 
ommatidia in the longest row. Otherwise as holotype. 

Holotype worker, Botswana: Okavango Delta, Maxwee, grassland, sample no. 26, 10.x. 1975 
(A. Russell-Smith) (BMNH). 
Paratypes. 7 workers with same data as holotype (BMNH; MCZ). 
Non-paratypic material examined. Botswana: Maxwee (A. Russell-Smith). 

One of the smallest members of the salomonis-group and one of the most reduced, in terms of pilosity 
and sculpture. M. rabirium is characterized by the absence of dorsal pilosity, very faint sculpture, anterior 
shifting of the eyes, light colour and small size. The position of the eyes in this species is reminiscent of the 
setuliferum-group , but the basal tooth of the mandible is not markedly reduced in size, the scapes are 
longer than is seen in setuliferum and its allies, and the head in rabirium is narrower. As the eyes in esharre, 
a close relative, are slightly in front of the midlength it seems reasonable to assume that these two species 
are convergent upon the condition seen in the setuliferum-group as regards the eyes, whilst showing other 
diagnostic characters referring them to the salomonis-group. 

Mandibular sculpture in rabirium is much fainter than in other salomonis-group members, and for this 
reason the species runs out twice in the key, once with the members of the salomonis-group and 
setigerum-group where the mandibles are usually conspicuously sculptured, and once elsewhere among 
species where they are smooth. 



SOLENOPSIS GENUS-GROUP 359 

The closest relatives of rabirium are zulu and osiridis (mediocre-complex) which share the lack of pilosity 
and anteriorly shifted eyes. Also these species appear to have a palp formula of 1,2 (based in each case on 
an in situ count), lower than the usual PF 2,2 seen elsewhere in the group. M. osiridis, from Kenya, 
separates from rabirium by having the head conspicuously sculptured. For differentiation of rabirium and 
zulu see under the latter. 

Monomorium ruf'ulum Stitz stat. n. 
(Figs 27, 36, 42) 

Monomorium salomonis var. rufula Stitz, 1923: 156. Syntype workers, Namibia: Windhoek, v. 1911 

(Michaels en); Omaruru, 21-22. v. 1911 (Michaelsen) (MNHU) [examined]. 
Monomorium (Xeromyrmex) monardi Santschi, 1937: 224, figs 15, 16. Holotype worker, Angola: Osi, 

1932-33, no. 16 (A. Monard) (NMB) [examined]. Syn. n. 

Worker. TL 3-0-3-6, HL 0-76-0-88, HW 0-59-0-70, CI 75-80, SL 0-69-0-81, SI 112-120, PW 0-40-0-47, 
AL 0-98-1-16 (15 measured). 

Fourth (basal) tooth of mandible reduced to a minute denticle which is only a fraction the size of the third 
tooth. Ventral surface of head with numerous very long anteriorly curved J-shaped or strongly arcuate 
hairs. Maximum diameter of eye 0-23-0-26 x HW, with 10-12 ommatidia in the longest row. Median 
portion of clypeus with its anterior margin transverse to shallowly convex in full-face view. Dorsum of head 
with a maximum of 3 pairs of hairs behind the level of the frontal lobes, but in full-face view the sides and 
occipital margin without projecting hairs. Dorsal alitrunk usually hairless but in Namibian specimens the 
pronotal humeri with a single hair on each side. Petiole node with 1-2 and postpetiole with 2-3 pairs of 
posteriorly projecting hairs. First gastral tergite densely pilose, with about 10 pairs in front of the apical 
transverse row. Colour dull orange to reddish orange on head, alitrunk, petiole and postpetiole; the gaster 
darker brown to blackish brown but frequently with a much paler spot or streak anteromedially. Dorsum 
and sides of head and entirety of alitrunk densely reticulate-punctate, the punctures small, crowded and 
sharply defined. Petiole and postpetiole reticulate-punctulate, the punctulae less well defined than on the 
alitrunk. Gaster feebly shagreened basally, the sculpture fading apically. 

A distinctive and quite widespread member of the 6/co/or-complex in southern Africa, rufulum is 
immediately diagnosed by its reduced basal mandibular tooth, numerous long arched ammochaete hairs on 
the ventral surface of the head, and densely hairy first gastral tergite contrasting to the hairless (or nearly 
hairless) dorsal alitrunk. According to Arnold (1916) this species, which he wrongly gives as nitidiventre, is 
very agile and nests in loose sandy soil. Both alate and apterous females of rufulum are known. 

Material examined 

Angola: Osi (A. Monard). Namibia: Windhoek (Michaelsen); Namib Desert (A. C. Marsh). Botswana: 
Maxwee (A. Russell-Smith). Zimbabwe: Bulawayo (G. Arnold); Bembesi (G. Arnold). 

Monomorium senegalense Roger nomen dubium 
Monomorium senegalense Roger, 18626: 294. Syntype workers, Senegal (not in MNHU, presumed lost). 

From the short original description of this species it certainly belongs in the salomonis-group, and is very 
probably a member of the aus/ra/e-complex. Unfortunately nothing more definite can be said unless the 
type-series is rediscovered. It is interesting to note that in this complex dakarense and senegalense are the 
only members recorded from West Africa, and it is possible that senegalense may be a senior synonym of 
dakarense. 

Monomorium subdentatum Forel 

Monomorium subdentatum Forel, 1913a: 332. Syntype workers, Zaire: Katanga, Elisabethville, 
23.iv.1912 (Bequaert) (MHN; MRAC) [examined]. 

Worker. TL 3-1-3-3, HL 0-80, HW 0-63-0-66, CI 79-83, SL 0-66-0-68, SI 103-105, PW 0-42, AL 
0-94-0-98 (2 measured). 
Answering the description of opacum but differing as follows. 



360 B. BOLTON 

subdentatum opacum 

In profile propodeal dorsum and declivity meeting In profile propodeal dorsum and declivity 

in a sharply defined or subdentate angle. rounding together, not meeting in a sharp angle. 

SI 103-105. SI 90-100. 

Anterior free margin of median portion of clypeus Anterior free margin of median portion of clypeus 

concave. convex. 

Known only from a couple of syntypes and a short series from Kienge, Zaire, subdentatum is only feebly 
separated from opacum. Further collections may well provide intermediates in the characters mentioned 
above. The series from Kienge (in MCZ) differs from the syntypes as the alitrunk of the worker has a few 
minute standing hairs on the promesonotum and a quite densely hairy first gastral tergite. Whether this 
series represents a separate species, or whether the syntypes of subdentatum have been badly abraded, 
remains to be decided. 

Material examined 
Zaire: Shaba, Lubumbashi (Bequaert); Kienge (Ross & Leech). 

Monomorium subopacum (Smith) 

Myrmica subopaca Smith, 1858: 127. Syntype workers, females, Madeira (T. V. Wollaston) (BMNH) 

[examined] . 
Myrmica glyciphila Smith, 1858: 125. Syntype workers, Sri Lanka (BMNH) [examined]. Syn. n. [Rejected 

as prior name based on pagination, on the first reviser principle.] 
Monomorium mediterraneum Mayr, 1891: 72. Syntype workers, female, Spain (NMV) [not seen]. 

[Synonymy by Mayr, 1862: 753.] 
Monomorium subopacum (Smith) Mayr, 1862: 753. 
Monomorium salomonis st. subopacum var. senegalensis Santschi, 1913a: 306. Syntype workers, Senegal: 

Saint-Louis (Claveau) (NMB) [examined]. [Unavailable name.] 
Paraphacota surcoufi Santschi, 1919a: 90, fig. 1. Syntype males, Algeria: Biskra, viii.1917, at light 

(/. Surcouf) (NMB) [examined]. Syn. n. 
Paraphacota cabrerai Santschi, 1919c: 405, fig. 1. Holotype male, Canary Is: Teneriffe, Laguna, 25.vii. 

1918 (A. Cabrera y Diaz) (NMB) [examined]. Syn. n. 
Monomorium (Xeromyrmex) salomonis st. subopacum var. liberta Santschi, 1921a: 170. Syntype workers, 

Senegal: Saint-Louis (Claveau) (NMB) [examined]. [Syntypes of liberta are same specimens as 

senegalensis above. Unavailable name.] 
Paraphacota cabrerae [sic] st. obscuripes Santschi, 1921c: 424. Syntype males, Canary Is: Teneriffe, 

Bejairo, 20. ix. 1898 (Cabrera); Bejamar, 10.x. 1909 (Cabrera) (NMB) [examined]. [Synonymy by 

Santschi, 1927:241.] 
Monomorium (Xeromyrmex) salomonis subsp. subopaca var. claveaui Emery, 1922: 178. [Unnecessary 

replacement name for senegalensis Santschi. Unavailable name.] 
Monomorium (Xeromyrmex) salomonis subsp. subopacum var. santschiellum Wheeler, 1922: 872. 

[Unnecessary replacement name for senegalensis Santschi. Unavailable name.] 
Monomorium (Xeromyrmex) subopacum subsp. italica Baroni Urbani, 19646: 154, figs 2,3. Holotype 

worker, Italy: Gambarie (Aspromonte), viii.1957 (C. Conci) (MCSNV) [not seen]. [Synonymy by 

Baroni Urbani, 19686: 450.] 

Worker. TL 3-1-3-4, HL 0-70-0-82, HW 0-54-0-64, CI 76-79, SL 0-58-0-68, SI 102-110, PW 0-36-0-42, 
AL 0-88-1-00 (15 measured). 

Anterior free margin of median portion of clypeus indented or concave at its midpoint. Maximum 
diameter of eye 0-27-0-30 x HW, with 9-1 1 ommatidia in the longest row. With the alitrunk in profile the 
mesonotum sloping evenly back to the metanotal groove, the latter only very slightly impressed. Dorsum 
of head in profile without standing hairs behind the level of the frontal lobes or, very rarely indeed, with a 
single pair situated just behind the level of the posterior margin of the eye . Dorsal alitrunk without standing 
hairs. Petiole and postpetiole each with a single pair of backward directed hairs or rarely the postpetiole 
with two pairs. First gastral tergite with an apical transverse row of hairs and also with a single pair situated 
at or close to the midlength. Exceptionally a second pair may occur between the pair at the midlength and 
the gastral base. Dorsum of head reticulate-granulate to shagreenate-punctulate, the sculpture blanketing 
the surface. Usually the mid-dorsal longitudinal strip of the cephalic sculpture with a smeared appearance 
or even with a longitudinally oriented sculptural pattern; the constituents of the sculpture not as sharply 



SOLENOPSIS GENUS-GROUP 361 

defined as on the sides above the eyes. Promesonotal dorsum sculptured much as the head on its anterior 
portion, but posteriorly becoming more plainly reticulate or even reticulate-punctate. Propodeal dorsum 
reticulate to reticulate-punctate. First gastral tergite with superficial patterning only, which is usually 
denser basally than apically. Colour brown, varying in shade but usually with the gaster darker than the 
head and alitrunk. 

This species is widely distributed in Africa north of the Sahara, ranging from Morocco in the west to 
Egypt in the east, and also occurring in the drier parts of the states bordering the northern and eastern 
shores of the Mediterranean. It is well established on most islands in the Mediterranean Sea and is present 
on Madeira, the Cape Verde Islands, the Canary Islands, and Ascension Island. It seems probable that the 
species may be widely distributed in the Sahelian zone of Africa but to the present I have seen only the 
single sample from Niger, noted below. Three short series examined, one from South Africa, one from Sri 
Lanka and one from Madagascar, certainly represent casual introductions by man in historic times as they 
are well away from the normal range of this species. Previous notes on distribution of this species in 
sub-Saharan Africa given in Wheeler (1922) and elsewhere should be treated with great caution as 
misidentifications of specimens were rife in the salomonis-group. 

Material examined 

Afrotropical region. Niger: Niamey (P. Room). Senegal: Saint-Louis (Claveau). South Africa: Durban 
(C. P. van der Merve). 

Other regions. Madagascar: Maevantanara (J. M. Wilson). Sri Lanka: noloc. (ex coll. Smith). Madeira: 
(T. V. Wollaston); Porto Santo (N. L. H. Krauss); Porto Santo (Lindberg). Cape Verde Is: many small 
samples {Lindberg). Ascension I. (E. A. G. Duffey). Gibraltar (J. J. Walker). Sardinia (E. Saunders). 
Morocco: Tiferhial, nr Tiznit (Meinander). Israel: Sea of Galilee (J. Palmoni); Jordan Valley, Dagania A 
(J. Palmoni). Egypt: Siwa (/. Omer-Cooper); Neviot, E. Sinai (C. R. Vardy). 

Monomorium sutu sp. n. 

Holotype worker. TL 2-9, HL 0-73, HW 0-56, CI 77, SL 0-58, SI 104, PW 0-40, AL 0-94. 

Median portion of clypeus with anterior free margin transverse to shallowly convex. Head in full-face 
view with sides evenly weakly convex, broadest at the level of the eyes; the sides more obviously 
convergent behind than in front of the eyes. Occipital margin broadly but shallowly concave. Eyes 
relatively large, the maximum diameter 0-36 X HW and with 12 ommatidia in the longest row. Eyes 
situated at the midlength of the sides in full-face view and distinctly larger than in any other member of the 
australe-complex. Promesonotal dorsum in profile sloping shallowly and evenly posteriorly, the metanotal 
groove indicated by a weak incised line across the dorsum but not impressed. Petiolar peduncle 
anteroventrally with a very low flange-like process. Dorsum of head with a single pair of short standing 
hairs behind the level of the frontal lobes, situated approximately at the level of the posterior margins of the 
eyes when the head is viewed in profile (in the holotype the left hand hair of this pair is missing). Occipital 
margin of head and all of dorsal alitrunk without standing hairs. Petiole and postpetiole each with a single 
pair of backward directed hairs. First gastral tergite with 2 pairs of standing hairs in front of the apical 
transverse row; one pair situated at about the midlength of the tergite, the second somewhat closer to the 
base. Dorsum of head opaque, blanketed by fine and dense reticulate-shagreenate to punctate- 
shagreenate sculpture; mid-dorsally the surface with exceptionally fine dense scratch-like longitudinal 
sculpture. Dorsal alitrunk finely and densely reticulate to reticulate-punctate. First gastral tergite very 
densely and finely shagreenate, opaque but dully shining. Head in front of eyes yellowish brown, 
posteriorly the head becoming darker brown. Sides of head below level of eyes lighter than dorsum. 
Promesonotum yellowish brown and lighter than head, but propodeum, petiole, postpetiole and gaster 
much darker, the last very dark brown. 

Paratype Workers. TL 2-7-3-0, HL 0-68-0-75, HW 0-50-0-57, CI 74-79, SL 0-54-0-59, SI 102-108; PW 
0-36-0-40, AL 0-84-0-94 (17 measured). As holotype but maximum diameter of eye 0-35-0-38 x HW and 
with 10-12 ommatidia in the longest row. Pilosity as holotype but some paratypes with only a single pair of 
hairs on the first gastral tergite (discounting the apical transverse row), this pair situated at the midlength of 
thesclerite. 

Holotype worker, Kenya: Tana River, Kora, 0-100 m, 1983, no. 19, Acacial Commiphila scrub (A/. M. 
Collins & M. Ritchie) (BMNH). 
Paratypes, 17 workers with same data as holotype (BMNH; MHN; MCZ). 



362 B. BOLTON 

The distinctive cephalic sculpture links sutu with opacior and its immediate allies, but sutu is quickly 
separated from these, and from all other members of the australe-complex, by its relatively very large eyes. 
Range of eye size throughout the remainder of the complex is 0-23-0-30 x HW, as compared to 
0-35-0-38 XHW in sutu. 

Monomorium tchelichofi Forel 

Monomorium tchelichofi Forel, 1914: 244. Syntype workers, South africa: Cape Prov., Willowmore 
(H. Brauns) (MHN; MCZ) [examined]. 

Worker. TL 3-8-4-0, HL 0-90-0-98, HW 0-74-0-82, CI 82-86, SL 0-74-0-80, SI 95-100, PW 0-46-0-52, 
AL 1-00-1-10 (10 measured). 

Anterior margin of median portion of clypeus evenly concave in full-face view. Head relatively short and 
broad (CI above) with evenly shallowly convex sides. Eyes of moderate size, the maximum diameter 
0-20-0-23 x HW and with 10—11 ommatidia in the longest row. Occipital margin indented medially, 
shallowly concave. Alitrunk in profile with promesonotum evenly convex, highest at junction of pro- and 
mesonotum, the latter sloping posteriorly to the weakly impressed metanotal groove. Propodeal dorsum 
shallowly concave transversely, the margins separating dorsum from sides rounded and not sharply 
defined. Dorsum of head with 3-4 pairs of standing hairs behind the level of the frontal lobes, all pairs 
straddling the midline and none close to the occipital corners. Dorsal alitrunk hairless. Petiole node with 
one pair, postpetiole with 2-3 pairs of backward directed hairs. First gastral tergite with short standing 
hairs sparsely but evenly distributed over the sclerite in front of the apical transverse row. Cephalic dorsum 
unsculptured except for superficial fine reticulate patterning. Dorsal alitrunk finely reticulate to reticulate- 
punctulate everywhere, the sculpture generally increasing in density and intensity from front to back. 
Dorsum of postpetiole with fine granulate to punctulate sculpture. First gastral tergite with fine and usually 
dense superficial reticulate patterning. Colour dark brown, the gaster usually darker in shade than the 
alitrunk. 

As mentioned under fridae, tchelichofi may well be a junior synonym of this name. For the present the 
sparse material of the two allows them to be separated on slight differences in size, but further samples may 
well annul the presumed differences. 

Material examined 
South Africa: Cape Prov., Willowmore (H. Brauns); Willowmore (G. Arnold). 

Monomorium termitarium Forel stat. n. 

Monomorium salomonis subsp. termitarium Forel, 1910c: 17. Syntype workers, female, Botswana: 
Kalahari, Kooa (L. Schultze) (MHN; BMNH) [examined]. 

For discussion of this species see under australe. 

Monomorium vatranum sp. n. 

(Fig. 55) 

Holotype worker. TL 2-8, HL 0-71, HW 0-52, CI 73, SL 0-60, SI 115, PW 0-34, AL 0-80. 

Median portion of clypeus with its anterior margin shallowly convex. With the head in full-face view the 
sides in front of the eyes roughly parallel, behind the eyes weakly converging posteriorly. Occipital margin 
broadly and very shallowly concave. Maximum diameter of eye 0-27 x HW and with 9 ommatidia in the 
longest row. Scapes long, SI > 110. Alitrunk in profile with promesonotum low and only very shallowly 
convex, the metanotal groove not or only vestigially impressed. Dorsum of head with 3 pairs of hairs 
straddling the midline behind the level of the frontal lobes, without hairs close to the occipital corners. 
Dorsal alitrunk with a single pair of hairs, situated at the pronotal humeri. Petiole and postpetiole each 
with a single pair of backward directed hairs. First gastral tergite with hairs sparsely but more or less evenly 
distributed over the sclerite in front of the apical transverse row. Cephalic dorsum with superficial reticular 
patterning, which may appear feebly shagreenate close to the occipital margin. Pronotal dorsum finely and 
densely reticulate, the sculpture becoming more sharply defined posteriorly on the alitrunk so that the 
propodeum is shallowly reticulate-punctulate. First gastral tergite smooth and shining, with superficial 
reticulate patterning only. Colour a uniform very dark brown. 



SOLENOPSIS GENUS-GROUP 363 

Paratype workers. TL 2-7-3-0, HL 0-62-0-74, HW 0-45-0-56, CI 72-76, SL 0-53-0-63, SI 113-120, PW 
0-34-0-36, AL 0-76-0-82 (12 measured). Maximum diameter of eye 0-27-0-29 x HW, with 9-10 ommati- 
dia in the longest row. As holotype but colour varying from medium brown to blackish brown, the colour 
usually uniform but sometimes the alitrunk slightly lighter than the head and gaster. 

Holotype worker, Namibia: Namib Desert, Swartbank 14° 50' E, 23° 16' S, sample S8, 15.vii.1981 (A C. 
Marsh) (BMNH). 

Paratypes, 11 workers with same data as holotype; 3 workers, Namib Desert, Ganab, 15° 37' E, 23° 08' S, 
sample 98, sandy plain, 16.viii.1981 (A. C. Marsh); 3 workers with same data as last but sample G24, 
5.v. 1981 ; 3 workers with same data but sample 187, 19.viii. 1981 ; 1 worker, Namib Desert, Mirabeb, 15° 24' 
E, 23° 25' S, sample M13, 8.iv.l982 (AC Marsh) (BMNH; MHN; MCZ). 

This small darkly coloured species is the Monomorium sp. B of Marsh (1984) and belongs to the 
Wator-complex. 

Monomorium viator Santschi 

(Figs 47, 52) 

Monomorium (Xeromyrmex) viator Santschi, 1923: 280, fig. 3. Syntype workers, male, Namibia: Namsen, 
22.xii.1925 (R. W. E. Tucker) (NMB) [examined]. 

Worker. TL 3-0-3-7, HL 0-80-0-96, HW 0-58-0-72, CI 73-77, SL 0-68-0-86, SI 111-1 19, PW 0-38-0-46, 
AL 0-92-1 -12 (15 measured). 

Median portion of anterior clypeal margin transverse to shallowly concave. Eyes relatively very large, 
the maximum diameter 0-37-0-40 x HW, with 13-15 ommatidia in the longest row. Promesonotal dorsum 
evenly convex and sloping posteriorly to the very feebly impressed metanotal groove, in some workers the 
groove virtually unimpressed. Propodeal dorsum flat to shallowly transversely concave. Dorsum of head 
with 2-3 pairs of standing hairs straddling the midline behind the level of the frontal lobes. Dorsal alitrunk 
without hairs. Petiole with one pair and postpetiole with 1-2 pairs of backward directed hairs. First gastral 
tergite with hairs present in front of the apical transverse row, relatively few in number but more or less 
evenly distributed over the sclerite; often with a tendency to be more concentrated on the basal half. 
Dorsum of head finely and densely reticulate to reticulate-shagreenate. Dorsal alitrunk reticulate to 
punctulate-granular on the pronotum, the sculpture generally becoming coarser and more conspicuous 
posteriorly but sometimes more or less even on the entire surface. First gastral tergite glossy and with 
superficial reticular patterning. Head and gaster usually darker in colour than the alitrunk. Alitrunk 
varying from yellowish orange to reddish brown, the head and gaster proportionally darker, ranging from 
light reddish to dark brown, with or without a reddish tint. In some the head may be bicoloured, with the 
posterior half lighter in shade than the anterior. Clypeus, mandibles and appendages are frequently dull 
yellow. 

A very distinctive and conspicuous species of the Namib Desert, viator is rendered easily recognizable by 
its long scapes and relatively very large eyes, coupled with its lack of standing hairs on the alitrunk. 

This is the species referred to by Marsh (1984) as Monomorium sp. A in his Namib Desert pitfall studies, 
and as can be seen from the material examined, appears to be one of the commoner species in the desert 
areas which he sampled. 

Material examined 

Namibia: Namib Desert, Skeleton Coast (A C Marsh); Unjab Riv. (A C Marsh); Samanab Riv. 
(A C Marsh); E. Dune Field (A C. Marsh); Tsondab Vlei (A C Marsh); Ganab (A C Marsh); 
Swartbank (A C Marsh); Namsen (R. W. E. Tucker). 

Monomorium westi sp. n. 

(Figs 37, 43) 

Holotype worker. TL 3-0, HL 0-78, HW 0-60, CI 77, SL 0-65, SI 108, PW 0-40, AL 0-90. 

Fourth (basal) tooth of mandible about the same size as the third tooth , not reduced to a minute denticle . 
Prominent median portion of clypeus with its anterior free margin strongly concave, the concavity flanked 
on each side by a sharp projecting tooth. With the head in full-face view the eyes at the midlength of the 



364 B. BOLTON 

sides, maximum diameter of eye 0-23 x HW, with 10 ommatidia in the longest row. Occipital margin of 
head weakly indented medially, the sides evenly but very shallowly convex, almost straight. Alitrunk in 
profile with metanotal groove only feebly indicated, not sharply impressed. Propodeal dorsum not sharply 
marginate laterally, the mid-dorsal longitudinal strip of the propodeum only very weakly indented. 
Petiolar peduncle with a small anteroventral lobe-like process. Height of petiole node from spiracle to 
summit greater than the length of the anterior peduncle from spiracle to anteriormost point of the ventral 
process. Petiole node bluntly conical in profile, distinctly higher than the postpetiole node. In dorsal view 
both nodes of approximately equal width. Dorsum of head with 1-2 pairs of hairs behind the level of the 
frontal lobes, without hairs projecting from the sides of the head or from the occipital margin. Ventral 
surface of head with numerous projecting fine curved hairs and with a very long anteriorly curved pair 
behind the buccal margin. Dorsal alitrunk without standing hairs. Petiole node with one pair, and 
postpetiole with 3 pairs of backward directed hairs. First gastral tergite with hairs more or less evenly 
distributed over the sclerite, with about 7-8 pairs in front of the apical transverse row. First gastral sternite 
densely hairy. Dorsum and sides of head and all surfaces of alitrunk finely and densely reticulate-punctate, 
the individual punctures small, densely crowded and sharply defined. Petiole and postpetiole similarly 
sculptured but the punctures less sharply defined. First gastral tergite finely shagreenate, the sculpture 
densest basally and becoming more feeble apically. Head, alitrunk, petiole, postpetiole and appendages 
orange to dull orange, the gaster blackish brown to black, the two colours strongly contrasting. 

Paratype workers. TL 3-0-3-2, HL 0-80-0-84, HW 0-60-0-65, CI 73-80, SL 0-64-0-68, SI 105-110, PW 
0-40-0-43, AL 0-92-0-96 (6 measured). As holotype but maximum diameter of eye 0-22-0-25 x HW, with 
9-10 ommatidia in the longest row. Dorsum of head at most with three pairs of standing hairs behind the 
level of the frontal lobes; postpetiole with 3-4 pairs of backward directed hairs. 

Holotype worker, Kenya: Kora, 8.xii.l983, sample ATI Acacia tortius (C. West) (BMNH). 
Paratypes, 3 workers with same data as holotype; 2 workers with same data but 30.xii.1983, sample AT3 
(BMNH;MCZ;MHN). 

A distinctive member of the bicolor-complex, with strongly developed dense reticulate-punctate 
sculpture and conspicuously contrasting colour pattern, westi is diagnosed by its strongly concave 
anteromedian clypeal margin which is flanked by a pair of sharp, freely projecting teeth, a character not 
seen in any other species of the complex. 

Apart from this westi has much smaller eyes than personation (0-31-0-33 x HW), lacks the reduced basal 
tooth and ammochaete hairs diagnostic of rufulum, lacks the dense alitrunk pilosity seen in hirsutum, and 
has the gaster much more densely hairy than in bicolor itself. 

The species was discovered by Mr Christopher West of Oxford University whilst sampling the insect 
fauna of Acacia trees. The ants were collected from sheets spread around the bases of trees which had been 
sprayed with insecticide to bring down the insect fauna. As other members of the bicolor-complex are 
terrestrial rather than arboreal I suspect that the specimens of westi had walked onto the sheets after 
spraying was complete, and were killed by residual insecticide. 

Monomorium willowmorense sp. n. 

(Fig. 54) 

Monomorium salomonis r. herrero [sic] var. willowmorensis Forel, 1914: 245. Syntype workers, South 
Africa: Cape Prov., Willowmore (G. Arnold) (BMNH; MHN) [examined]. [Unavailable name.] 

Monomorium salomonis r. herrero [sic] var. belli Forel, 1914: 245. Syntype workers, South Africa: Cape 
Prov., Willowmore (G. Arnold) (BMNH; MHN; MCZ) [examined]. [Unavailable name.] 

Syntype workers. TL 2-5-3-0, HL 0-62-0-72, HW 0-50-0-60, CI 79-83, SL 0-44-0-54, SI 88-93, PW 
0-33-0-39, AL 0-70-0-88 (12 measured). 

Anterior free margin of median portion of clypeus shallowly convex to approximately transverse, never 
concave or sharply indented medially. Eyes of moderate size , the maximum diameter 0-24-0-26 x HW and 
with 8-10 ommatidia in the longest row. Antennal scapes with SI < 100. With alitrunk in profile the 
promesonotum more or less evenly shallowly convex, the highest point approximately at the midlength. 
Metanotal groove shallowly to feebly impressed, generally better marked in larger than in smaller workers. 
Propodeal dorsum weakly flattened to shallowly concave posteriorly and between the propodeal angles 
where dorsum meets declivity. Petiole and postpetiole nodes in dorsal view both broader than long, of 
approximately equal width. Head mid-dorsally smooth and polished, with only the faintest traces of 



SOLENOPSIS GENUS-GROUP 365 

superficial reticular patterning. Closer to the occipital margin the reticular pattern is denser and more 
conspicuous, and the patterning is usually more distinct on the sides above the eyes than on the dorsum. 
Dorsal alitrunk with sculpture becoming stronger from front to back. Pronotum anteriorly finely reticulate, 
the propodeum finely reticulate-punctate. Petiole and postpetiole nodes weakly reticulate-granular. First 
gastral tergite superficially reticulate, the pattern usually more distinct basally than apically. All dorsal 
surfaces of head and body with sparse appressed pubescence but standing hairs very sparse. On the head 
the dorsum lacks hairs behind the level of the frontal lobes and hairs are entirely absent from the dorsal 
alitrunk. The petiole has one pair and the postpetiole 2 pairs of backward directed hairs. First gastral 
tergite with 2-3 pairs of hairs as well as an apical transverse row. Colour medium brown, the gaster usually 
slightly darker in shade than the alitrunk. 

Syntypes, 20 workers, South Africa: Cape Prov. , Willowmore, i. 1914 and 1 .i. 1914; bearing the numbers 
165 or 166 in red ink under the card mount, or with the numbers 208 or 219 in pencil on the upper surface of 
the card mount (MHN and MCZ material may lack these numbers) (G. Arnold) (BMNH; MHN; MCZ). 

Non-syntypic material examined. South Africa: Cape Prov., Willowmore (H. Brauns); Grahamstown 
(W. L. Brown). 

This small but fairly distinctive species seems closest related to the even smaller Namibian kitectum. 
Differences separating them are given in the key. 

Monomorium zulu Santschi 

Monomorium zulu Santschi, 19146: 18. Syntype workers, South africa: Natal, Zululand, Junction of 
Umfolozis, lO.vii. 1905 (/. Tragardh) (NMB) [examined]. 

Worker. TL 1-7-1-8, HL 0-44-0-46, HW 0-34, CI 74-77, SL 0-29-0-30, SI 85-88, PW 0-20-0-22, AL 
0-44-0-46 (2 measured). 

Very closely related to rabirium (mediocre-complex) and sharing its diagnostic characters, as given 
under the description of rabirium. The two differ in the following features. 
rabirium zulu 

Maximum diameter of eye 0-26-0-28 x HW, with Maximum diameter of eye 0-24-0-26 x HW, with 

7-8 ommatidia in the longest row. 5-6 ommatidia in the longest row. 

SI 92-97. SI 85-88. 

Cephalic dorsum with traces of superficial reticular Cephalic dorsum smooth with scattered small pits 

patterning close to occipital margin. close to occipital margin. 

Pronotal dorsum reticulate to shagreenate. Pronotal dorsum smooth. 

Despite these differences I suspect that future collections of these forms made between their respective 
type-localities in Botswana and South Africa may well show a gradation of one form into the other. 

Material examined 
South Africa: Natal, Zululand (/. Tragardh). 

The setuliferum-group 

(Figs 57-59) 

Worker. Monomorphic but with some size variation in any given series. Palp formula 2,2 (alamarum, 
setuliferum) . Mandibles usually with 4 teeth, the basal tooth reduced to a small or minute denticle which is 
offset from the main row of 3 teeth. Basal denticle lost in one species (havilandi) leaving the mandible 
3-dentate. Mandibles longitudinally striate or rugose (smooth in xanthognathum) . Median portion of 
clypeus raised and weakly bicarinate, not strongly projecting forward and the anterior clypeal margin 
lacking prominent teeth or angles. Posteriorly the median portion of the clypeus broader than either 
frontal lobe where it passes between them. Cephalic sculpture variable, sometimes absent. Eyes moderate 
to very large (0-22-0-36 x HW) and situated in front of the midlength of the sides of the head. In profile the 
eyes usually conspicuously oblique and frequently reniform in shape. Head generally short and broad 
(CI > 85), but narrower in alamarum and macrops. Scapes relatively short, SI usually <90. Antennae with 
12 segments, terminating in a strongly differentiated club of 3 segments. Propodeal dorsum smooth to 
reticulate-punctate, never transversely striate or rugose. Propodeal spiracle circular to subcircular. 
Petiolar spiracle at the node or immediately in front of the anterior face of the node. (Workers examined: 
all members of group. ) 



366 B. BOLTON 

Female. Characters as worker but alate when virgin and with fully developed flight sclerites; distinctly 
larger than conspecific worker. Eyes larger than worker and ocelli present. (Female examined: havilandi.) 

Male. Distinctly much larger than the conspecific worker, closely approaching size of female. Mandibles 
with 3-4 teeth, the blades longitudinally rugose or striate. Palp formula 2,2 (notulum). Antennae with 13 
segments, the scape short cylindrical, two or more times longer than broad. First funicular segment shorter 
than remainder but not globular; remaining funicular segments cylindrical to barrel-shaped, elongate, not 
tapering or whip-like apically. Eyes large and at the midlength of the sides, with a broad space between 
their anterior margins and the clypeus (as in Fig. 25). Sides of head behind eyes converging to the broad 
occipital margin. With the head in full-face view the ocelli not breaking the occipital outline. Notauli absent 
but parapsidal furrows represented by a pair of unsculptured strips on the mesoscutum. HW slightly 
greater than maximum width of mesoscutum. Cross-vein m-cu absent from forewing. Axillae triangular, 
small and lateral on the dorsum. Propodeal spiracle small and circular. (Males examined: notulum, 
havilandi.) 

This is a convenience group, erected to hold 8 southern African species which probably do not represent 
a holophyletic group but which are nonetheless linked by the characters listed above. The included species 
show, in the workers, features of both the salomonis-group and the destructor-group, but do not fall 
convincingly into either. Males on the other hand are most emphatically of the salomonis-group form and 
are in fact inseparable from those of members of that group. Based on material presently available the 
members of the setuliferum-group appear most likely to have been derived from two loci, or perhaps more, 
within the salomonis-group, but have converged on the destructor-group in a number of ways in the worker 
caste. See the notes under the introduction to the species-groups. 

The members of this group fall into three complexes of species, as follows. 

The setuliferum-comp\ex, including the three very closely related species ebangaense, notulum, and 
setuliferum, and a couple of peripheral but related taxa. The three named are very close indeed and may 
eventually prove to be expressions of a single plastic species. Within the group the three are characterized 
by a lack of standing pilosity on the head and body , presence of strong sculpture , possession of oblique eyes 
which may or may not be reniform, and presence of relatively broad heads and short scapes (CI 83-90; SI 
81-90). Peripheral to this triad is alamarum, which shares most of the above characters but has very 
reduced sculpture and a slightly larger head (CI 79-83), and has a lower petiole node (Fig. 58), although 
the significance of this last feature cannot be assessed at present. Also peripheral to the three species noted 
above is hannonis, a species obviously close to setuliferum but differing in the form of its sculpture and its 
development of dense pilosity. These five together may well represent a holophyletic group based on their 
sculpture and eye form, combined with the joint characters of the group diagnosis given above. 

The havilandi-complex contains only havilandi and xanthognathum , in which the large eyes are oblique, 
reniform in the latter but not so in the former. Scapes are relatively short (SI 70-82) and the broad head (CI 
86-92) is smooth and unsculptured except for scattered hair-pits. Both species show numerous standing 
hairs on the head, alitrunk and gaster. 

These two are grouped here on what are probably convergencies, and are not really closely related, but 
so little material of either is available for study that any pronouncements made now would amount to little 
more than speculation. Suffice to say that the havilandi worker is one of only two known Afrotropical 
species of Monomorium to have only 3 teeth on the mandible (the other being abyssinicum). It could have 
been derived from the setuliferum-complex above, or independently derived from the salomonis-group. 
The male, described by Arnold (1944), is of the salomonis-group form. 

M. xanthognathum shows some resemblance to the destructor-group but has eyes which are too large and 
are wrongly shaped to allow its admittance to that group. Also, the diagnostic destructor-group character of 
possession of transverse sculpture on the propodeal dorsum is absent here. The discovery of the male of 
xanthognathum would help our understanding of its taxonomic position, but I would guess that the male 
would be salomonis-\ike rather than destructor-like. 

The macrops-complex contains only macrops. In this species the eyes are large and shifted forwards, but 
are only slightly oblique and are not reniform. The head is quite long (CI 78-80) but the scapes are 
relatively short (SI 84-90). Sculpture is extremely reduced on the head but present on the dorsal alitrunk; 
the head, alitrunk and first gastral tergite all retain standing hairs. 

Certainly this species represents a development from the salomonis-group independent of any of those 
listed above. Its origins are presently very obscure but it seems a reasonable hypothesis that its 
resemblances to both of the complexes discussed above are the result of convergence rather than of real 
relationship. 



SOLENOPSIS GENUS-GROUP 367 

Monomorium alamarum sp. n. 

(Fig. 58) 

Holotype worker. TL 2- 1, HL 0-60, HW 0-49, CI 82, SL 0-40, SI 82, PW 0-29, AL 0-56. 

Eyes large, conspicuously in front of the midlength of the sides, the maximum diameter of the eye 
0-33 x HW and with 8-9 ommatidia in the longest row. In profile the eye distinctly oblique, with its long 
axis tilted at about 35° to the long axis of the head. The anterior lobe of the eye drawn out anteroventrally 
down the side of the head and the eye feebly reniform. In profile the promesonotum evenly convex, the 
metanotal groove not impressed. Dorsal surfaces of head, alitrunk, petiole and postpetiole without 
standing hairs of any description, but with very sparse fine appressed pubescence present. First gastral 
tergite with similar appressed pubescence but without standing hairs except for an apical transverse row. 
Dorsum of head everywhere with vestigial very fine superficial reticular patterning. Dorsal alitrunk more 
strongly sculptured, finely reticulate-shagreenate on the pronotum to closely reticulate or even reticulate- 
punctate on the propodeum. First gastral tergite with fine superficial reticular patterning as on the head. 
Colour uniform dark brown. 

Paratype workers. TL 2-0-2-4, HL 0-56-0-68, HW 0-45-0-56, CI 79-83, SL 0-38-0-50, SI 80-90, PW 
0-26-0-32, AL 0-52-0-66 (12 measured). As holotype but maximum diameter of eye 0-33-0-36 x HW and 
with 8-10 ommatidia in the longest row. 

Holotype worker, Namibia: Namib Desert, Ganab, 15° 37' E, 23° 08' S, sample G 339, 10. vi. 1982 (A. C. 
Marsh) (BMNH). 

Paratypes. 11 workers with same data as holotype; 6 workers, Namib Desert, Tsondab Vlei, 15° 22' E, 
23° 55' S, sample T6, 4.iv.l982 (A. C. Marsh) (BMNH; MCZ). 

Within the setuliferum-group as defined above alamarum is a very conspicuous species, rendered easily 
recognizable by the form of its eyes coupled with the lack of standing pilosity on head, alitrunk, and first 
gastral tergite in front of the apical row, and the superficial reticular patterning faintly present on the head. 
In all other species included in the group either standing hairs are numerous (havilandi, xanthognathum, 
macrops), or the head is very obviously densely sculptured (ebangaense, notulum, setuliferum), or both 
(hannonis). 

Monomorium ebangaense Santschi stat. n. 

Monomorium (Xeromyrmex) bicolor st. ebangaense Santschi, 1937: 223, figs 17-19. Holotype worker, 

Angola: Ebanga, 1932-33, no. 142 (A. Monard) (CdF) [examined]. 
Monomorium (Xeromyrmex) nyasae Arnold, 1946: 63, figs 14, 14a. Syntype workers, Malawi: Mt Zomba 

foothills, 10. xi. 1943 (SAM) [examined]. Syn. n. 

Worker. TL 2-5-2-7, HL 0-60-0-64, HW 0-54-0-57, CI 88-90, SL 0-46-0-50, SI 84-88, PW 0-34-0-37, 
AL 0-70-0-74 (5 measured). 

Very close indeed to notulum and matching the description given for that species, but the eyes averaging 
slightly smaller, maximum diameter 0-23-0-26 x HW (as opposed to 0-25-0-28 x HW in notulum). 
Otherwise ebangaense and notulum differ only by the minor sculptural characters noted in the key. On the 
whole ebangaense has more sharply defined and intense cephalic and pronotal sculpture than notulum, 
where it appears amorphous or smeared. This apparent difference in sculpture may well be a gradient 
character and hence unreliable, but as material is in short supply the two may be kept separate for the 
present. I suspect that further collecting will see ebangaense and its junior synonym nyasae, fall into the 
synonymy of notulum. 

M. nyasae, synonymized with ebangaense above, shows only a slight variation in colour which I do not 
consider sufficient to maintain it as separate from ebangaense. The former is dull yellow, varying in shade 
over the body, whilst the latter is dull brownish yellow on the head and alitrunk, and blackish brown on the 
gaster. 

In the original description of ebangaense Santschi very erroneously related it to bicolor, and presented 
some startlingly inaccurate and misleading drawings of the holotype. In reality ebangaense is closest to 
notulum and setuliferum, and should not be confused with any member of the 6i'co/or-complex except 
superficially perhaps with rufulum, because that species shows a reduced basal tooth on the mandible as 
does ebangaense. M. rufulum, however, has very long strong ammochaete hairs ventrally on the head, is 



368 B. BOLTON 

larger (HW 0-59-0-70), has a much narrower head and longer scapes (CI 75-80, SI 112-120), has eyes 
situated at the midlength of the sides (Fig. 42), and has the first gastral tergite densely hairy. 

Material examined 
Angola: Ebanga (A. Monard). Malawi: Mt Zomba foothills (no collector's name). 

Monomorium hannonis Santschi 

Monomorium hannonis Santschi, 1910: 358. Syntype workers, Congo: Brazzaville (A. Weiss) (NMB; 
MR AC) [examined]. 

Worker. TL 2-7-2-8, HL 0-68-0-70, HW 0-60-0-61, CI 86-90, SL 0-52-0-53, SI 85-88, PW 0-39-0-40, 
AL 0-76-0-78 (3 measured). 

Head short and broad (CI, above), the eyes distinctly in front of the midlength of the sides. Maximum 
diameter of eye 0-22-0-23 x HW, with 8-9 ommatidia in the longest row. Eyes weakly reniform in profile, 
the anterior angles of the eyes drawn out anteroventrally into a lobe. Metanotal groove shallowly 
impressed, the propodeum rounding broadly and evenly into the declivity. Postpetiole very swollen in 
profile, dome-lie and conspicuously much more voluminous than the petiole. In dorsal view the postpetiole 
more than twice the area of the petiole node but both segments broader than long. All dorsal surfaces of 
head and body with numerous standing hairs, the hairs subdecumbent on the first gastral tergite but erect to 
suberect elsewhere. Several pairs of hairs present on the propodeal dorsum. Occipital margin with 
projecting hairs across the width and on the curve of the occipital corners in full-face view, but none on 
sides of head where only short appressed pubescence is present. All surfaces of head, alitrunk, petiole, 
postpetiole and basal third of the first gastral tergite very densely reticulate-punctate, the sculpture sharply 
defined. Punctures fading out to superficial reticulation posteriorly on the first gastral tergite. Colour 
brown, the gaster slightly darker in shade than the head and alitrunk. 

A very conspicuous and easily recognized member of the setuliferum-group , hannonis is isolated by its 
combination of dense blanketing reticulate-punctate sculpture and numerous standing hairs on all dorsal 
surfaces of the body. In other species of the group either hairs are absent from the cephalic dorsum, 
alitrunk and first gastral tergite in front of the apical transverse row (alamarum, ebangaense, notulum, 
setuliferum) , or sculpture is feeble to absent on the head and alitrunk dorsum {havilandi, macrops, 
xanthognathum) . 

Material examined 

Congo: Brazzaville (A. Weiss). 

Monomorium havilandi Forel 

Monomorium havilandi Forel, 1910b: 443. Syntype workers, female, South Africa: Natal (Haviland) 

(MHN) [examined]. 
Monomorium (Xeromyrmex) distinctum Arnold, 1944: 11, figs 18a-f. Syntype workers, males, South 

Africa: Natal, Weenen, x.1939 (H. P. Thomasset) (SAM; MCZ) [examined]. Syn. n. 
Monomorium distinctum var. leviceps Arnold, 1958: 119. Syntype workers, South Africa: Cape Prov., 

Sundays River, vi.1955 (N. Myers) (BMNH) [examined]. Syn. n. 

Worker. TL 2-8-3-1, HL 0-72-0-76, HW 0-62-0-67, CI 86-90, SL 0-49-0-55, SI 78-82, PW 0-40-0-43, 
AL 0-74-0-80 (14 measured). 

Mandibles with three teeth only, without trace of a reduced fourth tooth or offset denticle as is usual in 
this group. Eyes not reniform but their ventral margins flat to very shallowly concave, their dorsal margins 
broadly convex, so that the anterior angle of the eye is narrower and much more narrowly rounded than the 
posterior angle. Maximum diameter of eye 0-27-0-30 x HW and with 10-12 ommatidia in the longest row. 
Head relatively short and broad in full-face view, and the scapes short (CI 90 or less, SI <85). Metanotal 
groove weakly impressed. Short standing hairs present on all dorsal surfaces of head and body, numerous 
on the first gastral tergite but sparse or rarely absent on the propodeum. Occipital surface of head with 
superficial reticular patterning at least medially, and dorsum usually with a patch of similar or even fainter 
patterning in the area immediately behind the frontal lobes, but otherwise the head entirely featureless and 
smooth except for small hair-pits. Promesonotum dorsally finely superficially reticulate, the surface 
appearing weakly shagreenate to feebly punctulate in places. Propodeal dorsum finely reticulate-punctate. 
Sides of alitrunk with faint vestiges of sculpture on the pronotum, the remainder densely reticulate- 



SOLENOPSIS GENUS-GROUP 369 

punctate. First gastral tergite unsculptured and smooth from base to apex, highly polished. Colour uniform 
blackish brown to black, the gaster often shiny jet black. 

M. havilandi, recorded only from South Africa, is very easily diagnosed as this is the only Afrotropical 
Monomorium except for the very disinctive abyssinicum which has only three teeth present on the 
mandible. All other Afrotropical species have 4 teeth, 3 teeth plus a basal denticle, or in one species 
(latinode), 5 teeth. 

In the synonymy havilandi and leviceps are a perfect match, but distinctum shows slightly stronger 
promesonotal sculpture and has more sharply defined and denser hair-pits on the cephalic dorsum. This is 
regarded as a very minor character variation, without taxonomic significance at species-level. 

Due to a misidentification by Santschi (1917), havilandi was treated for some time as a subspecies of 
australe (thus in the catalogues of Wheeler (1922) and Emery (1922)). That Santschi's description was 
based almost entirely on havilandi and not australe is indicated by his diagnosis of the mandibles as 
tridentate, a character correct for havilandi but not for australe where the usual 4 teeth of the salomonis- 
group are present. 

Material examined 

South Africa: Natal, Weenen (H. P. Thomasset); no loc. (Haviland); Cape Prov., Sundays River (TV. 
Myers); Port Elizabeth (W. L. Brown); Grahamstown (Weatherill & Brown). 



Monomorium macrops Arnold stat. n. 

(Fig. 59) 

Monomorium mediocre subsp. macrops Arnold, 1944: 11, figs 17, 17a. Syntype workers, South Africa: 
Cape Prov., Victoria West (R. Smithers) (BMNH) [examined]. 

Worker. TL 2-0-2- 1 , HL 0-54-0-56, HW 0-42-0-45 , CI 78-80, SL 0-38, SI 84-90, PW 0-27-0-28, AL 0-54 
(3 measured). 

Eyes relatively large, maximum diameter 0-31-0-33 x HW, with 8-9 ommatidia in the longest row. 
Outline shape of body as Fig. 59; the metanotal groove weakly impressed and the petiole with a fairly large 
and conspicuous anteroventral process. Standing pilosity present on head and body but sparse. On the 
cephalic dorsum three pairs of hairs are present which straddle the midline behind the level of the frontal 
lobes. The first pair is situated at about the level of the midlength of the eye, the second behind the level of 
the eye, and the third at the occipital margin. On the occipital margin is another pair of hairs, situated close 
to the corners. Pronotum with a pair of standing hairs at the humeri, mesonotum with or without a short 
pair anteriorly, propodeum hairless. Petiole with one pair and postpetiole with two pairs of backward 
directed hairs. First gastral tergite with several pairs of hairs on the basal half, the apical half apparently 
hairless except for the marginal transverse row. Dorsum of head unsculptured except for hair-pits and faint 
superficial reticular patterning at the occipital border and immediately behind the frontal lobes. Promeso- 
notum weakly reticulate dorsally, the propodeum weakly reticulate-punctulate. First gastral tergite 
smooth, with vestigial superficial reticular patterning basally. Colour light to medium brown, the gaster 
slightly darker than the head and alitrunk. 

Arnold originally described this form as a subspecies of mediocre, but in fact macrops is a very distinctive 
species, not closely related to mediocre which has smaller eyes (0-21-0-24 x HW) situated at the midlength 
of the sides, lacks standing hairs on the head, alitrunk and first gastral tergite (except for the apical 
transverse row), and retains cephalic sculpture. In fact macrops, known only from the South African 
type-series, is something of an enigma. 

As the setuliferum-group is presently defined macrops should be included, but it has a number of features 
which strongly indicate that it has acquired these characters independently of any other member of the 
group. For instance, the sculpture and pilosity of macrops appear to represent a reduction of that seen in 
the mediocre-complex and elsewhere in the salomonis-group. The head remains relatively long and narrow 
(CI 78-80), approached only by alamarum (CI 79-83) and outside the combined range shown by the 
remaining species of the group (CI 83-92). The eyes of macrops, though large and shifted forward, are not 
as oblique as in most species (compare Figs 57-59), and the petiole has a relatively large anteroventral 
process. In summary the origins of macrops remain shrouded in mystery. Though indubitably it is derived 
from somewhere in the salomonis-group, it must have arisen from a part of the group different from any 
other species placed in the setuliferum-group as it is presently constructed. 



370 B. BOLTON 

Material examined 
South Africa: Cape Prov., Victoria West (R. Smithers). 

Monomorium notulum Forel stat. n. 

Monomorium setuliferum var. notula Forel, 1910£>: 441. Syntype workers, male, South Africa: Natal 

(Haviland) (MHN) [examined]. 
Monomorium (Xeromyrmex) setuliferum var. dolichops Santschi, 1928: 194. Syntype workers, Zimbabwe: 

Victoria Falls (G. Arnold) (NMB) [examined]. Syn. n. 
Monomorium (Xeromyrmex) setuliferum var. latior Santschi, 1928: 195. Syntype workers, Angola: 

Quifangondo (F. Silvestri) (NMB) [examined]. Syn. n. 

Worker. TL 2-0-2-4, HL 0-53-0-60, HW 0-46-0-52, CI 83-87, SL 0-38-0-42, SI 81-87, PW 0-29-0-34, 

AL 0-59-0-68 (15 measured). 

Eye in profile distinctly in front of midlength of side, its anterior angle drawn out into a lobe or blunt 
point which is directed anteroventrally; the eye not reniform but very obviously much more narrowly 
rounded anteriorly than posteriorly. Maximum diameter of eye 0-25-0-28 x HW and with 8-9 ommatidia 
in the longest row. Shape and size of eye showing variation even in a single series. Ventral surface of head 
with elongate curved hairs present. Metanotal groove impressed in profile. Standing hairs extensively 
suppressed on dorsal surfaces of body; absent from head behind level of frontal lobes, absent from 
alitrunk, absent from first gastral tergite in front of the apical transverse row. Fine appressed pubescence is 
present on all dorsal surfaces of head and body. Dorsum of head blanketed by reticulate-punctate to 
reticulate-shagreenate sculpture, the mid-dorsal area commonly overlaid by extremely fine scratch-like 
striolae. Punctate component of sculpture not sharply defined on posterior third of cephalic dorsum but 
instead with a smeared or amorphous appearance, which may extend over the whole head in some cases. 
Pronotal dorsum with partially effaced or shagreened reticulate-punctate sculpture, remainder of alitrunk 
finely reticulate-punctate. First gastral tergite reticulate-shagreenate basally, fading out to superficial 
reticular patterning apically. Colour brown, varying from yellowish to dark, but usually with the gaster 
darker in shade than the alitrunk. 

Very closely related to ebangaense, notulum is separated only by the minor sculptural characters noted in 
the key and its slightly larger eyes. Both of these are close to, and perhaps inseparable from, setuliferum 
where the eyes are larger still but tend to be distinctly reniform in shape. Within the bounds of the 
setuliferum-group as defined above , these three forms are distinguished by their dense blanketing sculpture 
and very reduced dorsal pilosity. 

Material examined 

Angola: Quifangondo (F. Silvestri). Zimbabwe: Springvale (G. Arnold); Hillside (G. Arnold); 
Bulawayo (G. Arnold); Victoria Falls (G. Arnold). South Africa: Natal (Haviland); Transvaal, Nelspruit 
(M. Samways). 

Monomorium setuliferum Forel 

(Fig. 57) 

Monomorium setuliferum Forel, 1910c: 16. Syntype workers, Botswana: Kalahari, Khakea (L. Schultze) 
(MHN; MCZ) [examined]. 

Worker. TL 2-5-2-7, HL 0-54-0-63, HW 0-47-0-55, CI 86-90, SL 0-40-0-49, SI 85-90, PW 0-30-0-35, 
AL 0-64-0-74 (15 measured). 

Eyes conspicuously in front of midlength of sides, markedly oblique with respect to the long axis of the 
head and usually distinctly reniform in profile , drawn out into a lobe anteroventrally which extends forward 
and downward on the side of the head anteriorly. Shape of eye variable even in a single series but 
conforming to this general pattern. Maximum diameter of eye 0-29-0-33 x HW and with 9-10 ommatidia 
in the longest row. Ventral surface of head with a number of long, anteriorly curved hairs. Metanotal 
groove shallowly impressed in profile. Standing hairs extensively suppressed on dorsal surfaces; absent 
from head behind level of frontal lobes , absent from alitrunk , absent from first gastral tergite except for the 
apical transverse row. Nodes of petiole and postpetiole each with a single pair of backward directed hairs. 
Fine appressed pubescence is present on all dorsal surfaces. Dorsum of head blanketed by reticulate- 
punctate to reticulate-shagreenate sculpture, usually with an extensive mid-dorsal patch which has 



SOLENOPSIS GENUS-GROUP 371 

extremely fine scratch-like striolae superimposed on the ground-sculpture. Dorsum and sides of alitrunk 
finely and densely reticulate-punctate everywhere, dorsally the punctures usually more sharply defined on 
the propodeum than on the pronotum, laterally the pronotum often reticulate rather than reticulate- 
punctate. First gastral tergite reticulate-shagreenate basally, fading to superficially reticular apically on the 
sclerite. Colour varying from yellowish brown to dark brown, the gaster often darker in shade than the 
alitrunk; sometimes the head also darker than the alitrunk. 

M. setuliferum is distinguished from notulum and ebangaense only by relatively feeble characters 
pertaining to the size and shape of the eyes. Thus in setuliferum the maximum diameter of the eye is 
0-29-0-33 x HW and the eye in profile is conspicuously reniform. In notulum and ebangaense the eye 
averages smaller, maximum diameter 0-23-0-28 x HW and is not reniform but rather has the anterior 
angle drawn out into a more or less straight lobe which is directed anteroventrally on the side of the head. In 
both notulum and setuliferum the eye shows variation in shape, and further collecting may force the 
synonymy of all three names, as notulum and ebangaense are only separated by weak sculptural differences 
which may merely reflect variation in a single species. 

Material examined 
Botswana: Kalahari, Khakea (L. Schultze); Okavango Delta, Shorobe (A. Russell-Smith). 

Monomorium xanthognathum Arnold 

Monomorium xanthognathum Arnold, 1944: 9, fig*; 15, 15a. Syntype workers. South Africa: Cape Town, 
nr Lion's Head, 10. v. 1939 (BMNH; MCZ) [examined]. 

Worker. TL 1 -9-2-3, HL 0-48-0-56, HW 0-44-0-51 , CI 88-92, SL 0-30-0-37, SI 70-77, PW 0-26-0-30, 
AL 0-48-0-52 (3 measured). 

Mandibles unsculptured, smooth and shining; the only species in either the setuliferum-group or the 
Afrotropical salomonis-group fauna to have entirely smooth mandibles. Eyes conspicuously far in front of 
the midlength of the sides, the maximum diameter of the eye 0-32-0-33 x HW. In profile the eyes reniform 
and strongly oblique with respect to the long axis of the head. Anterior lobe of eye extending forward and 
downward on the side of the head and in larger workers almost rounding onto the ventral surface of the 
head. In full-face view the head broad and the scapes relatively short (CI > 85, SI <80). Metanotal groove 
deeply impressed in profile. Dorsal surfaces of head, alitrunk, petiole, postpetiole and gaster with sparse 
standing hairs present and with sparse but relatively long decumbent to appressed pubescence on head, 
alitrunk and gaster dorsally. Dorsal surfaces of head, alitrunk and gaster smooth and shining, unsculptured 
and featureless except for scattered hair-pits. Sides of alitrunk unsculptured except for the mesopleuron 
which is punctulate-rugulose, and the bulla of the metapleural gland which has some faint sculpture 
present. Colour glossy blackish brown to jet black, the mandibles conspicuously bright yellow. 

A very easily recognizable species, the form of the eyes and mandibles, and the form of sculpture and 
pilosity coupled with the dimensions given above render xanthognathum unlikely to be confused with any 
other Afrotropical Monomorium. 

The affinities of xanthognathum are, however, in doubt for, although it fits best with other members of 
the setuliferum-group it is the species which, except for its eyes, most resembles the constituents of the 
destructor-group. It would be useful to know the male of xanthognathum as this would probably solve 
the problem immediately, as the known males of the two groups are quite different. For the present, on the 
evidence of the form of the eyes and lack of transverse sculpture on the propodeal dorsum , I am inclined to 
place xanthognathum in the setuliferum-group rather than in the destructor-group. 

Material examined 
South Africa: Cape Town (no collector's name). 

The mo/iomorium-group 

(Figs 23, 61-92) 

Worker. Monomorphic, frequently with size variation in any series but without allometric variation. 
Mandibles unsculptured, the masticatory margin usually with 4 teeth which decrease in size from apex to 
base. More rarely the mandible with 3 teeth plus a minute basal denticle; a very few species with only 3 
teeth and none with 5 teeth. Trulleum small to obliterated, when present frequently closed. Palp formula 



372 B. BOLTON 

predominantly 2,2 but reduced to 1,2 in minute species. Median portion of clypeus raised, usually 
projecting forward anteriorly and longitudinally bicarinate but the carinae feeble or fading anteriorly in a 
few species. Median portion of clypeus posteriorly broader than either of the frontal lobes where it passes 
between them. Anterior clypeal margin without a widely separated pair of teeth although the anterior ends 
of the clypeal carinae may project as sharp angles or teeth. Cephalic dorsum unsculptured and glassy 
smooth except for scattered hair-pits. Eyes always present and distinct, size small to large (0-15-0-38 x 
HW) and generally with 4 or more ommatidia in the longest row. Eyes usually situated in front of the 
midlength of the sides in full-face view; close to or at the midlength in only a few species-complexes. Eyes 
roughly circular to elongate-oval in profile, never reniform or extended anterolaterally into a lobe. Head 
always longer than broad (CI 72-89), scapes very variable in length (SI 72-110). Antennae with 10 to 12 
segments, terminating in a strong club of 3 segments. Metanotal groove moderately to strongly impressed, 
with distinct cross-ribs. Propodeal spiracle circular to subcircular. Propodeal dorsum rounding into 
declivity, not angulate or dentate. Promesonotal dorsum unsculptured. Propodeal dorsum usually 
unsculptured but rarely it may be reticulate-punctate; never transversely striate or rugulose. Petiolar 
spiracle at the node. Body pilosity variable in distribution but usually conspicuous, only extremely rarely 
absent from the dorsal alitrunk. Mesopleuron and metapleuron often smooth but may retain faint 
sculpture. Petiole, postpetiole and gaster usually unsculptured, very rarely otherwise. (Workers exam- 
ined: all included in this revision plus about 50 extralimital forms of the group, including andrei Saunders, 
atomum Forel, carbonarium Smith, chinense Santschi, clavicorne Andre, cooperi Donisthorpe, cyaneum 
Wheeler, donisthorpei Crawley, ebeninum Forel, fieldi Forel, intrudens Smith, javanum Forel, laeve Mayr, 
minimum (Buckley), monomorium, orientale Mayr, triviale Wheeler, viridum Brown, wheelerorum 
DuBois.) 

Female. Characters generally as worker but female much larger; female slightly smaller to slightly larger 
than conspecific male. Eyes larger than in worker and positioned at or close to the midlength of the head. 
Ocelli present. Mandibles as worker but dentition much reduced or bizarre in some socially parasitic 
species. Antennae with 11 or 12 segments, with a 3-segmented club. HW greater than maximum width of 
mesoscutum or the two about equal. Alitrunk usually winged and with a full complement of flight sclerites, 
but several apterous forms are known {carbonarium, ebeninum, floricola, mictilis, minimum). Alitrunk 
long and narrow in dorsal view, long and low in profile. Parapsidal grooves distinct to absent. Axillae 
triangular in dorsal view, separated by a small mid-dorsal gap or just meeting at the midline; axillae 
partially to entirely fused to mesoscutum in apterous females. Forewings with cross-vein m-cu absent and 
the venation frequently much reduced, with many veins faint to vestigial and not tubular. Head, alitrunk 
and gaster usually unsculptured but some with weak sculpture on the head behind the lateral portions of the 
clypeus and behind the frontal lobes. Lateral alitrunk sometimes sculptured in part. First gastral tergite 
unsculptured. Pilosity always present on dorsal surfaces of body, often abundant. (Females examined: 
arboreum, balathir, boerorum, carbonarium, draxocum, ebeninum, egens, exchao, exiguum, fastidium, 
firmum, floricola, guillarmodi, hospitum, intrudens, mictilis, minimum, monomorium, musicum, 
occidentale , pergandei , rhopalocerum, rosae, rotundatum, schultzei, torvicte, plus 6 unidentified species.) 

Male. Slightly smaller to slightly larger than the conspecific female, much larger than the worker. 
Mandibles meeting medially at full closure, with 3 teeth and frequently also with a minute basal denticle. 
Palp formula 2,2 or 1,2. Scape cylindrical or subcylindrical, variable in length but usually about equal to the 
second funicular segment or a little longer. First funicular segment not globular, the remainder of the 
funiculus not strongly tapering apically, not whip-like. Head capsule wider behind the eyes than in front, 
the maximum head width about equal to the maximum width of the mesoscutum. Eyes large and sited just 
in front of the midlength; always a space present between eye and mandibular base in full-face view, the eye 
not touching the clypeus. Ocelli large but not born on a turret nor breaking the outline of the occipital 
margin. Mesoscutum overhanging pronotum anteriorly. Notauli absent and mesoscutum usually lacking a 
narrow V-shaped anteromedian area which is less sculptured than the surrounding area. Parapsidal 
grooves present to absent. Axillae small, triangular in dorsal view and separated by a small gap medially. 
Propodeal spiracle in front of the midlength of the side. Venation as alate female. Head sculptured, 
remainder of body variable but usually smooth, sometimes the mesoscutum and scutellum sculptured. First 
gastral tergite unsculptured. Genitalia large and partially exserted. Body with pilosity dorsally. (Males 
examined: cooperi, ebeninum, exchao, exiguum, floricola, monomorium, pergandei, rosae, plus two 
unidentified species.) 

This is the largest species-group currently recognized within Monomorium, containing 69 known 
Afrotropical species and an unknown but quite large number of extralimital forms. Members of the group 
occur in all zoogeographical regions but the group is predominantly Afrotropical. At least one member, 



SOLENOPSIS GENUS-GROUP 373 

floricola, is an accomplished and very widespread tramp-species in the tropics and subtropics. On occasion 
floricola also occurs in the temperate zones in hothouses and other constantly heated buildings. 

Most species of the monomorium-group are small to minute and are only poorly represented in 
collections. Their biologies are mostly utterly unknown but the vast majority of species inhabit the leaf 
litter or topsoil layer. Several nest and forage arboreally or subarboreally and some have only been found 
in trees. As elsewhere in this publication the species-group is defined on a world-wide basis, and 
fundamentally the group contains all those species whose monomorphic workers have mostly or entirely 
unsculptured head and body, reasonably large eyes, fewer than 5 mandibular teeth with unsculptured 
mandibular blades, PF 2,2 or less, a rounded propodeum, and conspicuous dorsal pilosity . As elsewhere in 
the genus the definitions based on females and males are somewhat less certain as so few are known, but 
males always lack cross-vein m-cu in the forewing and lack all those characters diagnostic of the 
scabriceps-group and the destructor-group. Further study will almost certainly detect ways to subdivide 
what is here termed the monomorium-group into smaller groups. I have attempted here to define 
meaningful species-complexes as they occur in the Afrotropical region but have not carried this investiga- 
tion over to the extralimital species. Shortage of material is a limiting factor in this survey and it is freely 
admitted that some of the Afrotropical species-complexes discussed below are for convenience only, whilst 
others certainly constitute holophyletic assemblages. 

The monomorium-group definition outlined above includes all the species previously placed in the 
subgenus Monomorium s.str. or given as related to M. minutum (now monomorium) in the catalogues of 
Wheeler (1922) and Emery (1922), with the exception of those species excluded in this study. Forms 
previously placed elsewhere but now added to the monomorium-group include the inquiline species 
formerly constituting Epoecus and Corynomyrmex, and the disparate forms with 11 -segmented antennae 
originally grouped together on the strength of this spurious character under the subgenus Lampromyrmex 
(- Mitara). 

Afrotropical species-complexes of the monomorium-group (based on workers) 

The altinode-complex. The members of this complex appear to constitute a holophyletic lineage and are 
linked by possession of the following characters. Clypeal carinae are sharp and conspicuous, close together 
posteriorly and widely divergent anteriorly. The anterior clypeal margin has a prominent median section 
which is flanked by a pair of teeth, denticles or projecting acute angles at the apices of the clypeal carinae 
(Fig. 62). Antennae 12-segmented and the scapes not reaching the occipital margin when laid straight back. 
With the head in full-face view the eyes are distinctly in front of the midlength of the sides; in profile the 
eyes are usually elongate-oval and have a maximum diameter 0-20-0-28 x HW. The head capsule in profile 
is somewhat dorsoventrally flattened, with the dorsum, venter or both flat to shallowly convex. Usually the 
head becomes deeper posteriorly. Petiole node high and narrow in profile (Figs 84-88), anteroposteriorly 
slightly compressed and the peduncle subtended by a small or inconspicuous anteroventral process. 
Postpetiole high and narrow, also anteroposteriorly compressed and with a high vertical anterior face. 

This quite conspicuous complex includes 9 species (altinode, angustinode , arnoldi, captator ; fugelanum , 
mirandum, occidentale , tynsorum, vonatu) which are very widely distributed in sub-Saharan Africa. The 
distinctive structure of the clypeus is shared with the /car//--complex and the leopoldinum-complex, but both 
of these lack the apomorphic petiole and postpetiole configuration shown by the altinode-complex. The 
female of occidentale is known but otherwise all sexual forms are unknown in this complex. 

The &a?(>-complex. The clypeus, antennae and head shape correspond to that seen in the altinode- 
complex but the eyes, situated in front of the midlength, are relatively very large (0-30-0-38 x HW), with 
their posterior margins at or very close to the midlength of the sides. Also the petiole is subconical in profile 
and the postpetiole rounded, lacking the characteristic shape of the foregoing complex. 

The four large-eyed species of this small complex (balathir, holothir, manir, katir) appear to be derived 
from the same source as the altinode-complex, that source may well be the leopoldinum-complex. All three 
share the same characteristic clypeal structure and it may be postulated that the altinode-complex consists 
of relatives of the leopoldinum-complex which have evolved a specialized petiolar and postpetiolar 
structure, whilst the katir-complex consists of relatives of the leopoldinum-complex which have evolved 
enlarged eyes. The female of balathir is known, males remain unknown in this complex. 

The leopoldinum-complex. Clypeus, antennae and head shape as described for the altinode-complex. 
Eyes in front of the midlength of the sides but of moderate size (0-18-0-27 x HW) . Petiole subconical and 
postpetiole rounded, lacking the high narrow aspect of the altinode-complex. 

The 6 species included here (borlei, lene, leopoldinum, pallidipes , rastractum, springvalense) have much 
the same general appearance as the two complexes noted above, but they lack the specialized petiole and 



374 B. BOLTON 

postpetiole of the altinode-comp\ex and the enlarged eyes of the katir-complex. All species of the 
leopoldinum-complex are of eastern or southern Africa, their sexuals are not known. 

The schultzei-complex. Clypeal carinae sharp, close together, parallel or only feebly divergent an- 
teriorly. Anterior margin of projecting median portion of clypeus without prominent acute angles, teeth or 
denticles. Antennae 12-segmented and relatively long (SI 95-110), the scapes when laid straight back 
reaching or slightly exceeding the occipital margin or rarely failing to reach the margin only by a mere 
fraction of their apical width . Eyes in profile appearing round or subcircular (rather than elongate-oval) , in 
full-face view the eyes at or close to the midlength of the sides; in general the posterior margins of the eyes 
are at the midlength. Head capsule in profile distinctly biconvex, not dorsoventrally flattened. Head 
deepest just behind level of eye or close to the midlength. Promesonotum and propodeum in profile each 
forming a distinct convexity, separated by the metanotal groove. Petiole node small and subconical in 
profile. Subpetiolar process inconspicuous, either a small anteroventral lobe or a narrow strip. Postpetiole 
in profile low and rounded, smaller than the petiole and lacking a high vertical anterior face. 

The 10 species included here (arboreum, bevisi, crawleyi, excensurae, fasciatum, firmum, kineti, 
schultzei, speluncarum, vecte) form a close-knit complex of related forms and probably represent a 
holophyletic lineage. The species are restricted to eastern and southern Africa and are apparently related 
to the rhopalocerum-comp\ex, whose members share a similar overall distribution. Males of the schultzei- 
complex remain unknown but females of arboreum , firmum and schultzei are represented in collections. 

The rhopalocerum-complex. Clypeal structure as in the sc/iu/fze/'-complex and also matching that 
complex in alitrunk, petiole and postpetiole structure. Eyes in the rhopalocerum-complex are more 
elongate than in schultzei and allies and are very obviously situated in front of the midlength of the sides. 
The antennal scapes when laid straight back from their insertions fail to reach the occipital margin (except 
in binatu where they just reach), and the antennae are always 12-segmented. The head capsule in profile is 
shallowly biconvex, its deepest point at about the midlength. 

On the whole the five southern and eastern African species included here (binatu, exchao, rhopa- 
locerum, symmotu, tablense) are remarkably similar to the members of the scWrzeZ-complex but have 
shorter scapes, forward shifted eyes and somewhat more flattened heads. Females are known for exchao 
and rhopalocerum, males for exchao alone. 

The strangulatum-complex. Clypeal carinae sharply developed, widely separated and only feebly 
divergent anteriorly. The points at which the clypeal carinae meet the anterior clypeal margin are not 
marked with prominent angles or denticles. Antennae with 11 or 12 segments and when laid straight back 
the scapes surpass the occipital margin (except in egens). With the head in full-face view the posterior 
margins of the eyes are approximately at the midlength of the sides. In profile the eyes are round to 
subcircular (rather than elongate-oval). Head capsule in profile distinctly biconvex, deepest just behind the 
level of the eye or at the midlength. Occipital margin usually convex in full-face view. Petiole with a long 
anterior peduncle, subtended by a minute anteroventral process. Postpetiole low and rounded. 

One species with 11 antennal segments (strangulatum) and four with 12-segmented antennae (drax- 
ocum, egens, gabrielense, noxitum) are included here. Of the five all but egens are obviously closely related, 
but in egens the anterior clypeal margin tends to be concave and the pronotum is flattened with accentuated 
angular humeri; features not seen in the other four. All species occur in western and central Africa and 
morphologically appear intermediate between the schultzei- and rhopalocerum-complexes and the malatu- 
complex. They are particularly close to the latter but lack its characteristic petiolar structure. Males are not 
known for any species in this complex but females of egens and draxocum have been examined. 

The ma/afw-complex. Characters of this small complex are the same as those of the strangulatum- 
complex, and species with both 11 and 12 antennal segments are also included here. The structure of the 
petiole is, however, different, the node of malatu-comp\tx members being high and either narrowly 
subconical or cuneate in profile. The anterior peduncle is short and stout, and is subtended by a relatively 
large anteroventral process which is usually in the form of a broad, anteriorly truncated lamellate strip. In 
most species the standing hairs of the head, alitrunk and gaster tend to be blunt or truncated apically. 

Of the five species represented here four (affabile, disoriente, malatu, tanysum) have 12 antennal 
segments, the fifth (dolatu) has only 1 1 . Most species are of west or central African origin but disoriente is 
known only from Tanzania. Sexual forms of all species remain to be discovered. 

The iyenasu-complex. A single rather strange species from Tanzania, iyenasu, is included here. Known 
only from the worker it is immediately diagnosed by its relatively large size for a member of the 
monomorium-group (HW > 0-70), 12-segmented antennae with short scapes (SI <80), small eyes (0T9 x 
HW) and very dense pilosity . It lacks obvious relatives among the Afrotropical fauna and may represent an 
introduction from outside the region. 

The bequaerti-comp\ex. A small complex containing only three species and characterized by possession 
of 11-segmented antennae and a relatively large postpetiole. In profile the postpetiole is equal to or 



SOLENOPSIS GENUS-GROUP 375 

somewhat more voluminous than the petiole, and has a long, gradually sloping posterior face. Of the 
species included here bequaerti is known only from Zaire, and pulchrum only from Zimbabwe, but rosae is 
widely distributed in west and central Africa. Males and females of rosae are known but they have not yet 
been found for the other two species. 

The boerorum-complex. A large complex of 21 species comprising all those forms which do not fit any of 
the above complexes, and hence merely lumped here for convenience. Of the species involved seven 
(exiguum, fastidium, guillarmodi, mictilis, spectrum, taedium, vaguum) have 11 antennal segments and 
usually show reduced eyes in which a single median longitudinal row of 2-4 ommatidia is enclosed by an 
outer ring of ommatidia. A number of species with 12-segmented antennae also show this eye structure 
(inquietum, rotundatum, shilohense, sryetum, trake) as does the tramp-species floricola. The remainder, 
which have 12-segmented antennae, all show a normal eye with two or more longitudinal rows of 
ommatidia within the outer ring (boerorum, braunsi, kelapre, lubricum, mavide, musicum, nuptualis, 
paternum, torvicte). These last named tend to have a narrow blade-like subpetiolar process. Despite this 
there is a tendency to variation in the characters mentioned and a few exceptions to the characters; it is not 
possible to make any meaningful division of the complex at the present time. 

The vast majority of species included here are restricted to the territories of southern Africa. Species 
which occur in southern Africa and elsewhere on the continent include exiguum, mictilis, and vaguum, but 
each of these names may conceal more than one valid species. Only three species are found away from 
southern Africa, namely inquietum (Zaire), spectrum (Gabon), and trake (Ghana). 

Monomorium affabile Santschi 

Monomorium affabile Santschi, 1926a: 235, fig. B. Holotype worker, Zaire: Banzyville (R. P. Augustin) 
(NMB) [examined]. 

Worker. TL 1-5, HL 0-42, HW 0-34, CI 81, SL 0-30, SI 88, PW 0-22, AL 0-40. 

Answering the description of malatu but smaller, with a narrower head and longer scapes; see 
comparative dimensions below. Clypeus constructed as in malatu but carinae sharply developed, divergent 
anteriorly and reaching the anterior margin at the anterolateral angles of the projecting portion of the 
clypeus. Maximum diameter of eye 0-24 x HW, and with 5 ommatidia in the longest row. With the head in 
full face view the sides subparallel. 

M. affabile and malatu are very closely related and eventually may even prove to be synonymous. Apart 
from the few minor differences mentioned above the main discriminating features which presently separate 
the two are the dimensions and ratios, as follows. 

affabile malatu 

TL 1-5 1-9-2-1 

HW 0-34 0-38-0-46 

CI 81 88-92 

SL 0-30 0-33-0-38 

SI 88 80-85 

PW 0-22 0-26-0-28 

AL 0-40 0-50-0-54 

Monomorium altinode Santschi 
(Fig. 85) 

Monomorium rhopalocerum var. altinodis Santschi, 1910: 359, fig. 4. Holotype worker, Congo: Brazza- 
ville (Weiss) (NMB) [examined]. 

Monomorium altinode Santschi; Santschi, 19146: 18. [Raised to species.] 

Monomorium altinode var. bondroiti Santschi, 19206: 10, fig. If. Holotype worker, Zaire: Upper Lukuga 
(Bondroit) (NMB) [examined]. Syn. n. 

Note. The holotype of bondroiti is badly damaged, the post-alitrunkal segments all missing. 

Worker. TL 1-7, HLO-48, HWO-37, CI 77, SL 0-32-0-33, SI 87-89, PW 0-24-0-26, AL0-48 (2 measured). 

Clypeal carinae sharply developed and strongly divergent anteriorly, the carinae and the median 

anterior clypeal margin forming a near-equilateral triangle. Projecting median portion of anterior clypeal 



376 B. BOLTON 

margin flanked by a low but quite broad triangular prominence or denticle on each side, which separates 
the transverse to shallowly concave anterior margin from the lateral margin of the projecting portion on 
each side. Maximum diameter of eye 0-22-0-24 x HW and with 6 ommatidia in the longest row. With the 
head in full-face view the eyes conspicuously in front of the midlength of the sides and the scapes, when laid 
straight back from their insertions, failing to reach the occipital margin. Sides of head very shallowly 
convex in full-face view, the occipital margin broad and very feebly concave medially. Promesonotal 
outline high and convex in profile, on a much higher level than the propodeum. Mesonotum sloping evenly 
to the shallowly impressed metanotal groove. Propodeal dorsum sloping posteriorly and rounding broadly 
into the declivity. Propodeal spiracle small but not pinhole-like, not dominating the side of the sclerite. 
Petiole node in profile high and narrow, anteroposteriorly compressed and narrowly rounded above. 
Postpetiole lower and more broadly rounded than petiole but with a vertical anterior face. All dorsal 
surfaces of head and body with standing hairs, the promesonotum with 5 pairs and the propodeum with 2 
pairs. Sculpture absent except for cross-ribs at the metanotal groove. Colour yellow. 

M. altinode is very closely related to arnoldi, fugelanum and tynsorum, the four together forming a very 
uniform agglomeration. On present evidence I regard them as separate species, but further collecting may 
reduce the taxonomic distance between some or all of them. For the present the four are separated by their 
dimensions and some small morphological features. Their critical dimensions compare as follows. 





SI 


HW 


CI 


Diameter of eye x HW 


arnoldi 


95-98 


0-40-0-41 


74-77 


0-20-0-22 


tynsorum 


90-95 


0-40-0-44 


78-81 


0-24-0-25 


fugelanum 


92-95 


0-36-0-39 


74-78 


0-26-0-28 


altinode 


87-89 


0-37 


77 


0-22-0-24 



Apart from this tynsorum, marginally the largest and broadest-headed species, has 7-8 pairs of hairs on 
the promesonotal dorsum (as opposed to 5 pairs in the remaining species), and has the petiole node 
somewhat thicker in profile than the remainder (Fig. 87). Its propodeal spiracle is not reduced in size and 
the curve of the promesonotal outline is not strongly convex. In fugelanum, which is relatively small and 
has the largest eyes of the four species under consideration, the propodeal spiracle is minute (Fig. 88) and 
the petiole node narrow. M. altinode (Fig. 85) has the shortest scapes of the four and has the promesonotal 
outline most strongly convex, whilst arnoldi (Fig. 86), the species with the longest scapes and smallest eyes, 
tends to develop a weak dorsolateral crest on the petiole node which may extend down the upper portion of 
the side of the node. 

Material examined 

Congo: Brazzaville (Weiss). Zaire: Upper Lukuga (Bondroit). 

Monomorium angustinode Forel 

(Fig. 84) 

Monomorium angustinode Forel, 1913a: 334. Syntype workers, Zaire: Katanga (= Shaba), Welgelegen, 
14.vi.1912, no. 123 (Bequaert) (MNH; BMNH; MRAC) [examined]. 

Worker. TL 1-9-2-0, HL 0-52-0-54, HW 0-39-0-40, CI 74-77, SL 0-36, SI 90-92, PW 0-26-0-28, AL 
0-54-0-58 (6 measured). 

Clypeal carinae well defined, widely separated and divergent anteriorly, terminating at the anterior 
clypeal margin in a pair of short projecting denticles. Anterior margin of prominent median 'portion of 
clypeus shallowly concave between the pair of short denticles, the latter separating the anterior and lateral 
margins of the median clypeus. Margin usually with a small indentation at socket of median seta. Maximum 
diameter of eye 0-24-0-26 x HW and with 7-8 ommatidia in the longest row. In full-face view the eyes 
distinctly in front of the midlength of the side and the antennal scapes, when laid straight back from their 
insertions, failing to reach the occipital margin. Occipital margin broad in full-face view, the sides straight 
to feebly convex behind the level of the eyes. Promesonotal dorsum shallowly convex in profile, the 
mesonotum sloping evenly to the narrow but distinctly impressed metanotal groove. Cross-ribs of 
metanotal groove short. Propodeal dorsum with a short convex portion immediately behind the mefanotal 
groove, the surface then sloping evenly backwards; the dorsum and declivity forming a single curve, the 
two not obviously separated. Propodeal spiracle small and placed high on the side of the sclerite. In dorsal 
view the spiracular orifices prominent, born at the apices of a pair of low tubercles, the dorsum between 



SOLENOPSIS GENUS-GROUP 377 

them broad and almost flat. Petiole high and narrow, scale-like and narrowly rounded above. Subpetiolar 
process a narrow inconspicuous strip. Postpetiole anteroposteriorly compressed, lower than the petiole 
and slightly more broadly rounded above, but with a high vertical anterior face. All dorsal surfaces of head 
and body with standing hairs present, the promesonotum apparently with 4-5 pairs though all specimens 
available show signs of abrasion. Apart from small hair-pits and the feeble cross-ribs at the metanotum the 
entirety of the head and body is devoid of sculpture. Colour light brownish yellow, the head and gaster 
tending to be somewhat darker than the alitrunk. 

M. angustinode belongs to the altinode-complex but is distinguished from all its close relatives by the 
shape of the propodeum and structure of the propodeal spiracles. 

Material examined 
Zaire: Shaba, Welgelegen (Bequaert) 

Monomorium arboreum Weber stat. n. 

(Fig. 65) 

Monomorium (Monomorium) minutum subsp. arboreum Weber, 1943: 360. Syntype workers, female, 
Sudan: Imatong Mts, 6200 ft (1890 m), 2.viii. 1939, no. 1397 (N. A. Weber) (MCZ) [examined]. 

Worker. TL 2-1-2-3, HL 0-48-0-60, HW 0-39-0-46, CI 77-81, SL 0-38-0-48, SI 96-104, PW 0-25-0-30, 
AL 0-54-0-68 (15 measured). 

Clypeal carinae narrow but sharply defined, moderately divergent anteriorly and not terminating in a 
pair of denticles at the anterior clypeal margin. Anterior margin and lateral margins of the prominent 
median portion of the clypeus meeting in a poorly defined obtuse angle. Maximum diameter of eye 
0-20-0-24 x HW and with 6 ommatidia in the longest row. Outer circle of ommatidia enclosing more than 
one longitudinal ommatidial row. In full-face view the eyes with their posterior margins at or just behind 
the midlength of the sides and the scapes, when laid straight back from their insertions, just reaching the 
occipital margin. Sides of head almost parallel but feebly convergent posteriorly, rounding broadly and 
evenly into the relatively short occipital margin; the latter almost transverse, only with the feeblest median 
concavity in full-face view. Promesonotum evenly convex in profile, the highest point just in front of the 
midlength. Metanotal groove broad but only shallowly impressed and the propodeal dorsum behind the 
groove shallowly sloping posteriorly. Apex of promesonotal convexity on a much higher level than the 
propodeal dorsum, and the propodeal spiracle large and very conspicuous. Propodeal dorsum and declivity 
meeting in a rounded angle, the two surfaces with decidedly different slopes and not forming a single 
sloping surface. Subpetiolar process varying from a small lobe to a small blunt triangle. Petiole node in 
profile relatively low, subconical, with a narrowly rounded dorsum. Postpetiole smaller than petiole, its 
dorsal surface evenly broadly rounded in profile. All dorsal surfaces of head and body with standing hairs 
present, the promesonotal dorsum with 4-6, or very rarely 7 pairs present. Mandibles and dorsum of head 
unsculptured except for small pits from which hairs arise. Mesopleuron reticulate. Metanotal groove 
strongly and conspicuously cross-ribbed, the cross-ribs extending down the sides of the alitrunk; alitrunk 
otherwise unsculptured, smooth and shining. Petiole, postpetiole and gaster unsculptured. Colour dull 
yellow, the head dorsally and the first gastral tergite usually slightly darker in shade than the alitrunk and 
often with a brownish yellow tint. 

Weber (1943) discovered this species nesting in humus about the base of a large fern which was growing 
epiphytically on a forest tree about 5 m above the ground. As indicated by the Kenyan samples noted 
below, which were taken from forest leaf litter, a subarboreal lifeway is not obligatory and it is more 
probably the case that arboreum is normally a litter-layer species which, in the case of Weber's sample, was 
taking advantage of a functional but unusual nest-site. 

Weber described arboreum as a subspecies of minutum Mayr, to which it is not truly related. M. 
arboreum belongs instead to the small complex of Afrotropical species mc\udingschultzi,firmum and their 
allies, and is a valid species in its own right. Its closest relative appears to be the Ethiopian crawleyi but that 
species has a very broad metanotal groove which forms a distinctive shallow U-shaped trough in the 
alitrunk outline. 

Material examined 

Sudan: Imatong Mts (N. A. Weber). Kenya: Narok, Loita Hills, Morijo (V. Mahnert & J. L. Ferret); 
Embu, Irangi For. Sta. (V. Mahnert & J. L. Ferret); Ishiara (V. Mahnert & J. L. Perret); Kirimiri For. (V. 
Mahnert & J. L. Perret); Taita Hills (V. Mahnert). 



378 B. BOLTON 

Monomorium arnoldi Forel 

(Fig. 86) 

Monomorium arnoldi Forel, 1913ft: 137. Syntype workers, Zimbabwe: Matopo Hills (G. Arnold) (BMNH; 
MHN;MCZ) [examined]. 

Worker. TL 2-0-2-1, HL 0-52-0-54, HW 0-40-0-41, CI 74-77, SL 0-38-0-40, SI 95-98, PW 0-23-0-25, 
AL 0-48-0-52 (7 measured). 

Clypeal carinae well developed, widely divergent anteriorly and running to the margin. Space between 
the carinae shallowly transversely concave in front of the level of the frontal lobes. Clypeal carinae 
terminating in a pair of projecting low denticles, the anterior margin of the prominent median portion of 
the clypeus shallowly concave between them. Maximum diameter of eye 0-20-0-22 x HW and with 5-6 
ommatidia in the longest row. With the head in full-face view the eyes distinctly in front of the midlength of 
the sides and the scapes, when laid straight back from their insertions, failing to reach the occipital margin. 
Sides of head straight to shallowly convex in full-face view, rounding posteriorly into the broad occipital 
margin, which is transverse to feebly concave. Promesonotum convex in profile, sloping posteriorly to the 
impressed metanotal groove; the latter traversed by short but conspicuous cross-ribs. Propodeal dorsum 
evenly convex, its spiracle small. Petiole node high and narrow, anteroposteriorly compressed and 
narrowly rounded above. Subpetiolar process a narrow and inconspicuous strip. Postpetiole with a high 
vertical anterior face, more broadly rounded above than the petiole node. All dorsal surfaces of head and 
body with standing hairs, the promesonotum with 5-6 pairs (possibly more as all available material is 
somewhat abraded). Head and body entirely smooth except for minute hair-pits, metanotal cross-ribs and 
some very faint sculptural vestiges on the mesopleuron. Colour yellow to light brownish yellow, glossy. 

Notes on the separation of arnoldi from its closest relatives are given under altinode. Arnold (1916: 233) 
says that he has only found this species running on the branches of an unidentified tree which had green 
bark, the bark being covered by 'a thin yellowish and parchment-like outer skin, which is also waxy.' He 
states that the colour of the ants matches the skin of the tree very closely so that they are difficult to detect 
even when moving. 

Material examined 
Zimbabwe: Matopo Hills (G. Arnold); Matopos, Bedze (G. Arnold). 



Monomorium balathirsp. n. 

Holotype worker. TL 2-3, HL 0-52, HW 0-39, CI 75, SL 0-38, SI 97, PW 0-26, AL 0-54. 

Clypeal carinae widely divergent anteriorly. Prominent median portion of clypeus with its anterior 
margin concave. Anterior and lateral margins of median portion of clypeus separated by a pair of low, 
weakly projecting triangular prominences. Eyes relatively large, 0-31 x HW and with 7-8 ommatidia in the 
longest row. In full-face view the posterior margins of the eyes just in front of the midlength of the sides. In 
profile the maximum diameter of the eye much greater than the distance separating the anteriormost point 
of the eye from the closest point of the mandibular insertion. Head capsule in profile dorsoventrally 
flattened. With the head in full-face view the antennal scapes, when laid straight back from their insertions, 
failing to reach the occipital margin. Sides of head very shallowly convex and the broad occipital margin 
with only the faintest trace of concavity in full-face view. Promesonotum in profile shallowly convex and 
sloping posteriorly to the narrow but conspicuously impressed metanotal groove. Metanotal cross-ribs 
short but sharply defined. Propodeal spiracle minute and pinhole-like. Petiole node in profile subconical, 
high and narrow and narrowly rounded above. Subpetiolar process a small elongate lobe. Postpetiole more 
broadly rounded above than petiole, the anterior face of its node almost vertical, the posterior face much 
more shallowly sloping. In dorsal view both nodes broader than long. Standing pilosity dense and 
conspicuous on all dorsal surfaces, the promesonotum with 8-9 pairs and those at the pronotal humeri and 
midlength of the promesonotum notably elongate. Sides of head both in front of and behind eyes with 
projecting suberect to subdecumbent hairs. Entire body smooth and shining, unsculptured except for 
scattered minute hair-pits and metanotal short cross-ribs. Colour glossy dark brown, the appendages dull 
yellow. 

Paratype workers. TL 2-2-2-3, HL 0-50-0-52, HW 0-37-0-39, CI 73-76, SL 0-36-0-38, SI 95-97, PW 
0-26, AL 0-54-0-55 (4 measured). As holotype but maximum diameter of eyes 0-30-0-32 x HW. 



SOLENOPSIS GENUS-GROUP 379 

Subpetiolar process may be reduced to a low narrow ridge. Promesonotal dorsum with 8-10 pairs of 
standing hairs. 

Holotype worker, Burkina Faso (U. Volta on label): Ougadougou, 6.ix.l970 (P. Room) (BMNH). 
Paratypes, 4 workers and 1 female with same data as holotype (BMNH; MCZ). 

This dark coloured, large-eyed and conspicuously hairy species is a very distinctive member of the group. 
In colour and eye size it is approached only by the Kenyan manir, but this species is less densely pilose and 
has shorter scapes, SI 89 as compared with 95-97 in balathir. Two other large-eyed Afrotropical species are 
known in this group which have the maximum eye diameter greater than 0-30 x HW, katir and holothir. 
Both these are yellow in colour and katir has only 2-3 pairs of hairs on the promesonotum besides having 
very large eyes (0-35-0-38 x HW). M. holothir has slightly shorter scapes (SI 92-94) than balathir, besides 
being much ligher in colour and somewhat smaller. 

Monomorium bequaerti Forel 
(Fig. 92) 

Monomorium (Martia) bequaerti Forel, 1913a: 334. Syntype workers, Zaire: Elizabethville, 20. hi. 1912 
(Bequaert) (MRAC, MHN) [examined]. 

Worker. TL 1-9, HL 0-50, HW 0-38, CI 76, SL 0-36, SI 95, PW 0-25, AL 0-54. 

Clypeal carinae moderately strongly developed and widely divergent anteriorly. Maximum diameter of 
eye 0-21 x HW and with 5 ommatidia in the longest row. Outer ring of ommatidia enclosing more than one 
longitudinal row. In full-face view the eyes conspicuously in front of the midlength of the sides and the 
scapes, when laid straight back, failing to reach the occipital margin. Antennae with 11 segments. Sides of 
head evenly very shallowly convex in full-face view, the occipital margin exceptionally shallowly concave, 
almost transverse. Promesonotal dorsum in profile convex, sloping posteriorly to the shallow and only 
feebly impressed metanotal groove. Propodeum convex and broadly rounded, the spiracle pinhole-like. 
Nodes of petiole and postpetiole longer than broad in dorsal view. In profile the petiole node a high, 
relatively narrow, bluntly subconical structure. Subpetiolar process a narrow rim anteroventrally. Post- 
petiole in profile with a shallowly convex anterior face, broadly rounded dorsum and very long gradually 
sloping posterior face, the postpetiole relatively large, about the same size as or even slightly larger than 
the petiole. Except for small hair-pits, cross-ribbing at the metanotal groove and some faint vestiges on the 
pleurae sculpture is absent from the head and body; all surfaces except those mentioned being smooth and 
highly polished. All dorsal surfaces of head and body with standing hairs present, the promesonotum with 5 
pairs. Colour a light glossy brown. 

Of the Afrotropical species in which the antennae are 11-segmented three, bequaerti, pulchrum and 
rosae, have the relatively large and characteristically shaped postpetiole indicated in Fig. 92. Among these 
three species rosae is a fairly common West and Central African form which is very dark in colour, being 
blackish brown to black. The other two are much lighter, and apparently less common. M. pulchrum from 
Zimbabwe is dull yellow and bequaerti from Zaire is glossy light brown. Apart from its colour bequaerti is 
characterized by its relatively high narrow petiole node which in dorsal view is longer than broad. In both 
other species the petiole node is conspicuously broader than long in dorsal view. 

Material examined 
Zaire: Elizabethville (Bequaert). 

Monomorium bevisi Arnold 

Monomorium bevisi Arnold, 1944: 10, figs 16, 16a. Syntype workers, Lesotho: xii.1938 (A. L. Bevis) 
(SAM) [examined]. 

Worker. TL 2-4-2-6, HL 0-60-0-63, HW 0-48-0-50, CI 78-80, SL 0-48-0-50, SI 100-106, PW 0-28-0-32, 
AL 0-66-0-72 (6 measured). 

Anterior clypeal margin with a median notch-like concavity between the apices of the clypeal carinae; 
the latter sharply defined and subparallel, only feebly divergent anteriorly. Clypeal margin at apices of 
carinae angulate but without projecting triangular teeth or denticles. Eyes of moderate size, maximum 
diameter 0-20-0-22 x HW and with 6-7 ommatidia in the longest row. The eyes positioned so that their 



380 B. BOLTON 

posterior margins are at the midlength of the sides in full-face view. Antennal scapes moderately long (SI 
100 or more), when laid straight back from their insertions either reaching or only fractionally failing to 
reach the occipital margin. Sides of head almost straight in full-face view both in front of and behind the 
eyes; the sides curving towards the occipital corners. Promesonotal dorsum a low shallow convexity in 
profile, descending behind to the narrow and shallowly impressed metanotal groove. Cross-ribs of 
metanotal groove short and inconspicuous. Propodeal spiracle small, pinhole-like. Propodeal dorsum 
somewhat flattened but rounding evenly into the declivity. Petiole peduncle with a very low rounded 
anteroventral process. All dorsal surfaces of head and body with numerous standing hairs; more than eight 
pairs present on the promesonotum. Entirely lacking sculpture except for the cross-ribs of the metanotal 
groove and some faint indications on the metapleuron. Colour a dingy light brown throughout. 

As Arnold (1944: 11) stated, this dingy brown species is related to firmum but has a much narrower 
metanotal groove which lacks the strong and conspicuous cross-ribs shown by firmum. Also the propodeal 
spiracle, which is large and dominates the side of the propodeum in firmum, is much smaller and 
pinhole-like in bevisi. 

Material examined 
Lesotho (A. C. Bevis). 

Monomorium binatu sp. n. 

(Fig. 78) 

Holotype worker. TL 2-0, HL 0-53, HW 0-39, CI 74, SL 0-41, SI 105, PW 0-26, AL 0-56. 

Clypeal carinae sharply defined, close together posteriorly and only weakly diverging anteriorly; 
subparallel anteriorly and running to the margin. Anterior clypeal margin between the carinal apices 
shallowly concave . Anterior and lateral margins of prominent median portion of clypeus confluent through 
a pair of broadly rounded angles, the two not separated by projecting sharp angles or denticles. Maximum 
diameter of eye 0-23 x HW and with 6 ommatidia in the longest row. In full-face view the posterior margins 
of the eyes conspicuously in front of the midlength of the sides of the head. Antennal scapes, when laid 
straight back from their insertions, just reaching the occipital margin. Sides of head behind eyes feebly 
convergent posteriorly, the occipital margin broad and extremely shallowly concave, almost transverse. 
Promesonotum in profile evenly shallowly convex, descending posteriorly to the broadly and quite deeply 
impressed metanotal groove. Metanotal cross-ribs fine and only weakly developed. Propodeal outline 
rising steeply from the metanotal groove, the propodeal dorsum sloping downwards posteriorly and 
approximately flat, rounding smoothly but quite abruptly into the near-vertical declivity. Peduncle of 
petiole elongate and subtended by a conspicuous anteroventral process in the form of a flange-like cuticular 
strip. Petiole node in profile high and subcorneal, narrowly rounded above. Anterior face of petiole node 
longer and less strongly sloping than posterior face so that the node is slightly inclined posteriorly. 
Postpetiole node lower and much more broadly rounded than that of the petiole. Standing hairs present on 
all dorsal surfaces but relatively sparse, the promesonotum with only 3 pairs. Sculpture absent except for 
scattered minute hair-pits and the faint metanotal cross-ribs. Colour yellow, the gaster slightly darker in 
shade than the head and alitrunk. 

Paratype workers. TL 1-9-2-0, HL 0-48-0-53, HW 0-37-0-39, CI 73-76, SL 0-36-0-41, SI 100-105, PW 
0-24-0-26, AL 0-52-0-56 (8 measured). Maximum diameter of eye 0-21-0-23 x HW and with 5-6 
ommatidia in longest row. The mesopleuron may have a faint band of vestigial sculpture running 
transversely at about the mid-length. In one worker the petiole node is almost upright, not inclined 
posteriorly as in the rest. 

Holotype worker, Zimbabwe (Rhodesia on label): Vumba Mts, nr Umtali, 11. hi. 1969 (W. L. Brown) 
(MCZ). 
Paratypes. 16 workers with same data as holotype (MCZ; BMNH). 

Closely related to rhopalocerum, symmotu and exchao, M. binatu separates from all of these by its 
possession of relatively long scapes and high inclined petiole node. The SI of binatu (100-105) contrasts to 
the combined SI 83-94 of the other three species and the node (Fig. 78) is very different in shape from those 
shown by its close relatives (Figs 77, 79, 81). The shape of the node is approached most closely by tablense 
(Fig. 80) but here the scapes fail to reach the occipital margin, the promesonotum is more strongly convex, 



SOLENOPSIS GENUS-GROUP 381 

the metanotal groove not so broadly impressed and the eyes are larger. Apart from this the petiole node in 
tablense is narrower than in binatu and has its anterior face somewhat concave in profile (Fig. 80). 

Monomorium boerorum Forel stat. n. 
(Figs 63, 91) 

Monomorium minutum var. boerorum Forel, 1910b: 442. Syntype workers, female, South Africa: 
Orange Free State, vii.6. (Wroughton) (MHN; BMNH) [examined]. 

Worker. TL 1-9-2-0, HL 0-50-0-54, HW 0-38-0-43, CI 76-80, SL 0-33-0-34, SI 80-86, PW 0-24-0-25, 
AL 0-54-0-56 (3 measured). 

Clypeal carinae feebly developed, visible posteriorly, divergent and fading out anteriorly. Prominent 
median portion of clypeus more or less evenly broadly convex across its entire width, its border not 
differentiated into anterior and lateral margins by a pair of angles or denticles. Maximum diameter of eye 
0-19-0-21 x HW and with 6 ommatidia in the longest row. With the head in full-face view the posterior 
margins of the eyes conspicuously in front of the midlength of the sides and the scapes, when laid straight 
back from their insertions, falling far short of the occipital margin. Head with sides shallowly convex in 
full-face view and broadening posteriorly to the beginning of the curve of the occipital corner. Occipital 
margin broad and very shallowly transversely concave. Promesonotum shallowly convex in profile, sloping 
posteriorly to the weakly impressed metanotal groove; the latter with short but distinct cross-ribs. 
Propodeal dorsum evenly convex, the spiracle small. Petiole node low and thickly subconical, bluntly 
rounded above. Anterior peduncle of petiole short and stout, with a flange-like anteroventral process. 
Postpetiole much smaller than petiole, more broadly rounded above. All dorsal surfaces of body with 
standing hairs, 3-4 pairs present on promesonotum. Lower half of mesopleuron reticulate and metanotum 
cross-ribbed, otherwise entire body without sculpture except for hair-pits. Body glossy brown. 

M. boerorum was originally described as a variety of the European minutum (= monomorium) , a species 
to which it is not at all closely related. The true affinities of boerorum are difficult to discern as it possesses a 
petiole and postpetiole structure similar to that of paternum and nuptuale but lacks their clypeal structure. 
It lacks the much enlarged propodeal spiracle characteristic of kelapre but apart from this the overall 
similarity with kelapre is striking. 

Material examined 
South Africa: Orange Free State {Wroughton). 

Monomorium borlei Santschi stat. n. 

Monomorium (Monomorium) springvalense var. borlei Santschi, 1937: 225, figs 22-24. Syntype workers, 
Angola: Sangeve, 1932-33, no. 110 (A. Monard) (NMB) [examined]. 

Worker. TL 1-9-2-0, HL 0-50-0-52, HW 0-40-0-41, CI 79-80, SL 0-36-0-38, SI 90-93, PW 0-25-0-26, 
AL 0-54-0-56 (2 measured). 

Median portion of clypeus sharply prominent anteriorly, the anterior and lateral borders of the 
prominence separated by obtuse but sharp angles and the anterior margin between the angles shallowly 
concave. Clypeal carinae moderately sharply defined, widely divergent anteriorly. Maximum diameter of 
eyes 0-22-0-24 x HW and with 7 ommatidia in the longest row. With the head in full-face view the eyes in 
front of the midlength of the sides and the antennal scapes, when laid straight back, failing to reach the 
occipital margin. In full-face view the sides of the head very feebly convex, the occipital margin broad and 
transverse to extremely shallowly concave. Promesonotum in profile convex anteriorly, the mesonotum 
posteriorly almost flat and sloping evenly to the narrow but distinctly impressed metanotal groove. 
Propodeal dorsum behind the metanotal groove following the same slope as the mesonotum; rounding 
broadly into the declivity. Propodeal spiracle large and dominating the side of the sclerite. Petiole with a 
low flange-like ventral process , the node bluntly subconical . Node of postpetiole lower than that of petiole , 
broader and more broadly rounded above. In dorsal view both nodes conspicuously broader than long. 
Standing hairs sparsely present on all dorsal surfaces of head and body; the promesonotum with 3 pairs, 
propodeum with 1 pair, petiole and postpetiole each with 1 pair. Almost entirely smooth and unsculptured 
except for hair-pits; the metanotal groove with short but sharply defined cross-ribs and the mesopleuron 
with a transverse strip of vestigial sculpture. Colour a uniform glossy dark brown. 



382 B. BOLTON 

Related to leopoldinum but differentiated by its longer scapes and much sparser pilosity , borlei is known 
only from the type-series. Originally described as a variety oispringvalense, borlei is very close indeed to 
that species but is darker in colour, has a larger propodeal spiracle and 3 pairs of standing hairs on the 
promesonotum. 

Material examined 
Angola: Sangeve (A. Monard). 

Monomorium braunsi Mayr 

Monomorium braunsi Mayr, 1901: 7. Syntype worker, South Africa: Port Elizabeth (H. Brauns) 
(BMNH) [examined]. 

Worker. TL 1-6, HL 0-43, HW 0-33, CI 77, SL 0-27, SI 82, PW 0-20, AL 0-44. 

Clypeal carinae of this minute species short, clearly visible only on central third of length of median 
portion of clypeus, fading out both anteriorly towards the free margin and posteriorly between the 
antennal insertions. Anterior clypeal margin evenly convex across central portion, without conspicuous 
angles or denticles separating the anterior and lateral borders of the median prominent section of the 
clypeus. Eyes relatively small, only 0-18 x HW and with 5 ommatidia in the longest row. In full-face view 
the eyes very distinctly in front of the midlength of the sides of the head. Antennal scapes, when laid 
straight back from their insertions, falling far short of the occipital margin. Sides of head very shallowly 
convex in full-face view and divergent posteriorly from front to back so that the width across the occiput is 
obviously greater than the width across the clypeus. Occipital margin nearly transverse, with only the 
feeblest hint of concavity medially. Head in profile dorsoventrally compressed, the ventral surface more 
convex than the dorsal. Promesonotum low and only weakly convex in profile, the metanotal groove very 
shallowly impressed and traversed by short cross-ribs. Propodeal dorsum shallowly convex and rounding 
broadly into the declivity. Propodeal spiracle minute and pinhole-like. Petiole with a short stout anterior 
peduncle, the latter with a small inconspicuous anteroventral process. Node of petiole low and broad in 
profile, broadly rounded above and with a bulging convex ventral border. Postpetiole smaller and lower 
than the petiole, its dorsal surface somewhat more broadly rounded. Cephalic dorsum with several pairs of 
standing hairs but alitrunk with only a single pair, situated at the pronotal humeri. Petiole, postpetiole and 
gaster all with standing hairs visible. Sculpture absent except for minute hair-pits and metanotal cross-ribs. 
Colour uniformly yellow. 

This minute yellow species is distinguished from its close relatives mavide, musicum and torvicte by its 
very reduced alitrunk pilosity and low broadly rounded petiole node. The subpetiolar process of braunsi is 
very reduced, being represented only by a low anteroventral prominence rather than the anteriorly 
truncated longitudinal cuticular strip seen in the other three species mentioned. 

Material examined 

South Africa: Port Elizabeth (H. Brauns). 

Monomorium captator Santschi 

Monomorium captator Santschi, 1932: 385, fig. 8 (without description). [Nomen nudum.] 
Monomorium (Monomorium) captator Santschi, 1936: 43. Holotype worker, Zaire: Ronga (NMB) 
[examined]. 

Worker. TL 1-8-1-9, HL 0-52-0-54, HW 0-41-0-42, CI 77-81, SL 0-36-0-38, SI 88-93, PW 0-26-0-28, 
AL 0-53-0-55 (5 measured). 

Clypeal carinae sharply developed, widely separated and divergent anteriorly, terminating at the 
anterior clypeal margin in a pair of low triangular prominences or denticles. Anterior margin of projecting 
median portion of clypeus concave between these triangular prominences and usually with an indentation 
at the site of the median setal socket. Maximum diameter of eye 0-24-0-26 x HW and with 6-7 ommatidia 
in the longest row. With the head in full-face view the eyes in front of the midlength of the sides and the 
scapes, when laid straight back from their insertions, failing to reach the occipital margin. Sides of head in 
full-face view evenly shallowly convex, the occipital margin broad and transverse to broadly and very 
shallowly concave. Alitrunk in profile with the promesonotum shallowly convex anteriorly and evenly 
sloping posteriorly to the weakly impressed metanotal groove. Cross-ribs of metanotal groove well 
developed but mostly only short; a few longer cross-ribs occur laterally, about at the level of the propodeal 



SOLENOPSJS GENUS-GROUP 383 

spiracle. Propodeal dorsum in profile with a very short convex area immediately behind the metanotal 
groove, the remainder of the surface more or less flat and sloping posteriorly. Dorsum and declivity of 
propodeum meeting in a broad curve. Propodeal spiracle large, larger than is usually seen in relatives of 
altinode (Figs 85-88) but smaller than that seen in such as kineti (Fig. 64). Petiole node in profile high and 
narrow, anteroposteriorly compressed and narrowly rounded above. Postpetiole more broadly rounded 
above and somewhat lower than the petiole, but with a conspicuous vertical anterior face. All dorsal 
surfaces of head and body with numerous standing hairs; the promesonotum with more than 8 pairs. Head 
and body unsculptured except for hair-pits, metanotal cross-ribs and some faint vestiges of sculpture on the 
lower mesopleuron. Colour glossy dull yellow, the head slightly darker in shade than the alitrunk. 

Among the immediate relatives of altinode and arnoldi are those species in which the petiole node is 
high, narrowly rounded and anteroposteriorly compressed, the postpetiole high and with a vertical 
anterior face, and the colour yellow (Figs 84-88). M. captator is distinguished among these forms by its 
relatively large propodeal spiracle and dense alitrunk pilosity. A comparison of critical measurements 
between captator and its closest relatives can be obtained from the dimensions given above and the table 
presented in the discussion of altinode. 

Material examined 
Gabon: Libreville (F. Brunck). Zaire: Ronga. 

Monomorium crawleyi Santschi 
(Fig. 69) 

Monomorium (Monomorium) crawleyi Santschi, 1930a: 66. Syntype workers, Ethiopia: Djem-Djem 
Forest, 8000 ft (2400 m) 26.ix.1926 (H. Scott) (BMNH; MCZ) [examined]. 

Worker. TL 2-3-2-4, HL 0-57-0-59, HW 0-45-0-47, CI 78-81, SL 0-45-0-46, SI 98-102, PW 0-28-0-29, 
AL 0-64-0-68 (12 measured). 

Anterior margin of prominent median portion of clypeus transverse to shallowly concave; the anterior 
and lateral margins of the prominent portion separated by obtuse angles, without projecting denticles or 
projecting sharp angles. Clypeal carinae sharply developed, subparallel, only very feebly divergent 
anteriorly and running to the anterior clypeal margin. Maximum diameter of eye 0-21-0-24 x HW and 
with 6-7 ommatidia in the longest row. With the head in full-face view the posterior margins of the eyes at 
or very close to the midlength of the sides of the head. Antennal scapes, when laid straight back from their 
insertions, just reaching the occipital margin. Sides of head behind eyes shallowly convex and somewhat 
convergent posteriorly in full-face view, the occipital margin with a short and shallow median indentation. 
Promesonotal outline in profile a shallow low even convexity, the extreme posterior portion of the 
mesonotum suddenly more steeply sloping. Metanotal groove a very broad shallow U-shaped identation. 
Propodeal dorsum and declivity behind the metanotal groove forming a single smoothly curved convexity. 
Propodeal spiracle large and conspicuous. Petiole node low and bluntly subconical in profile, trie 
anteroventral process of the elongate peduncle with a small lobiform anterior section and a narrow 
strip-like posterior tail which reaches back to the level of the petiolar spiracle. Postpetiole much smaller 
than the petiole, lower and more broadly rounded. All dorsal surfaces of head and body with standing hairs 
present, the promesonotum with 5-6 pairs. Entirety of head unsculptured except for minute hair-pits. 
Alitrunk unsculptured except for long conspicuous metanotal cross-ribs and some faint reticulation on the 
mesopleuron. Colour yellow, the cephalic dorsum and posterior portion of the gaster darker. 

The distinctive shape of the alitrunk and relatively large propodeal spiracle render this Ethiopian species 
easfly recognizable. Its closest known relative appears to be arboreum but here the alitrunk is differently 
shaped, compare Figs 65, 69. 

Material examined 
Ethiopia: Djem-Djem Forest (H. Scott). 

Monomorium elisor iente sp. n. 

(Fig. 83) 

Holotype worker. TL 1-8, HL 0-46, HW 0-37, CI 80, SL 0-34, SI 92, PW 0-23, AL 0-52. 
Projecting median portion of clypeus with a broad, more or less transverse anterior margin which is 



384 B. BOLTON 

separated from the lateral margins only by bluntly rounded angles, without trace of projecting denticles or 
prominences. Clypeal carinae widely separated and divergent anteriorly, reaching the anterior clypeal 
margin. Maximum diameter of eye 0-24 x HW and with 6-7 ommatidia in the longest row. With the head 
in full-face view the eyes only fractionally in front of the midlength of the sides and the antennal scapes, 
when laid straight back from their insertions, just failing to reach the occipital margin. Sides of head 
shallowly convex in full-face view, the occipital margin broad and almost transverse, only with a very small 
central indentation. Promesonotum in profile evenly convex, highest at about the midlength; the 
promesonotum much higher than the propodeum. Mesonotum sloping posteriorly to the broadly but 
shallowly impressed metanotal groove, the latter traversed by long strong cross-ribs. Propodeum highest 
immediately behind the metanotal groove, the surface behind this approximately flat and sloping 
posteriorly. Propodeal spiracle small. Petiole with a short anterior peduncle which is subtended by a 
conspicuous lamellate ventral process. Petiole node high and bluntly subconical in profile. Postpetiole in 
profile with a steep anterior face and much more gently sloping posterior surface. Standing hairs present on 
all dorsal surfaces of head and body, the promesonotum with 4-5 pairs. Head and body unsculptured 
except for hair-pits, strong metanotal cross-ribs and fine reticulate-punctation on the upper half of the 
mesopleuron behind the pronotal laterotergite. Colour glossy pale brown, the gaster slightly darker in 
shade than the head and alitrunk. 

Holotype worker, Tanzania ('Afr.Or.aH'): Bezirk-Bukoba, Buk. 26 (Viehmeyer) (NMB). 

The holotype of disoriente was originally mounted on the same pin as the lectotype of strangulation. The 
two are distinctly different species as the latter has only 11 antennal segments (12 in disoriente) and has 
small clypeal denticles present, among other features. Santschi's (1921ft) original description appears to 
refer only to the specimen now treated as lectotype of strangulatum , so the second specimen on the mount 
has been remounted and now constitutes the holotype of disoriente. 

The affinities of disoriente appear to lie with affabile, tanysum and their allies. For notes see under 
tanysum. 

Monomorium dolatu sp. n. 

Holotype worker. TL 1 -5, HL 0-40, HW 0-34, CI 85, SL 0-26, SI 76, PW 0-22, AL 0-43. 

Clypeal carinae sharply defined and only very weakly divergent anteriorly, the space between them 
feebly transversely concave and the carinae with the anterior clypeal margin extremely shallowly concave 
between their apices. Prominent median portion of clypeus strongly defined, its anterior and lateral 
margins meeting in sharp angles. The clypeal carinae terminate mesad of these angles and a small 
secondary carina or rugule arises at each angle and runs back towards the antennal socket, roughly 
paralleling the clypeal carina on each side . Maximum diameter of eye 0-21 x HW and with 5 ommatidia in 
the longest row. In full-face view the eyes in front of the midlength of the sides. Antennae with 11 
segments; the scapes, when laid straight back from their insertions, failing to reach the occipital margin. 
Outline of dorsal promesonotum in profile evenly rounded-convex, the metanotal groove narrow but 
distinctly impressed. Metanotal cross-ribs short but strongly developed and conspicuous. Propodeal 
spiracle small. Propodeal dorsum in profile highest immediately behind the metanotal groove then sloping 
steeply to its rounded junction with the declivity. Peduncle of petiole very short and stout in profile, 
subtended by a deep anteroventral process which runs back approximately to the level of the petiolar 
spiracle where it is confluent with the strongly convex posteroventral margin of the node . Petiole node high 
and narrow, wedge-shaped in profile and narrowly rounded above. Postpetiole smaller than petiole, with a 
vertical anterior face, more broadly rounded dorsum and sloping posterior face. All dorsal surfaces of head 
and body with standing hairs, those of the alitrunk and gaster relatively short and appearing blunt or 
truncated apically; promesonotum with 5-6 pairs of standing hairs. Sculpture absent except for metanotal 
cross-ribs and some weak reticulation on the mesopleuron. Colour yellow, the head posteriorly somewhat 
darker than the alitrunk; first gastral tergite traversed apically by a broad brown band. 

Paratype workers. TL 1-4-1-5, HL 0-38-0-40, HW 0-32-0-40, CI 84-87, SL 0-26-0-27, SI 76-81, PW 
0-22-0-23, AL 0-42-0-44 (3 measured). Maximum diameter of eye 0-19-0-21 x HW. Otherwise as 
holotype. 

Holotype worker, Cameroun: Nkoemvon, 1980, no. lib (D. Jackson) (BMNH). 

Paratypes. 3 workers with same data as holotype (BMNH; MCZ). 

Non-paratypic material examined. Ghana: Mampong (P. Room). Ivory Coast: Gagno (L. Brader). 



SOLENOPSIS GENUS-GROUP 385 

The non-paratypic material, one specimen from each locality, resembles the type-series very closely but 
the brown band across the first gastral tergite is paler and interrupted medially. 

The affinities of dolatu lie with the members of the malatu-comp\ex, despite its 11-segmented antennae. 
This is the only known Afrotropical species with 11 antennal segments which has the petiole and clypeus 
structured as described above, and is hence quite distinctive. 

Monomorium draxocum sp. n. 

Holotype worker. TL 1 -8, HL 0-41 , HW 0-34, CI 83, SL 0-36, SI 106, PW 0-22, AL 0-46. 

Clypeal carinae sharply developed, widely separated and subparallel, only very feebly divergent 
anteriorly and reaching the anterior clypeal margin. Prominent median portion of clypeus with its anterior 
margin sharply defined and very feebly concave between the apices of the carinae, the anterior and lateral 
margins of the prominence meeting in an obtuse angle but without projecting denticles. Maximum 
diameter of eye 0-23 x HW and with 5 ommatidia in the longest row. In full-face view the eyes situated 
close to the midlength of the side of the head. Antennal scapes, when laid straight back from their 
insertions, slightly exceeding the occipital margin. Sides of head behind eyes shallowly convex and 
rounding broadly into the weakly convex occipital margin. In profile both the dorsal and ventral surfaces of 
the head markedly convex (shape very similar to gabrielense. Fig. 76). Promesonotal dorsal outline high 
and domed-convex in profile, on a very much higher level than the propodeal dorsum. Mesonotum 
descending steeply posteriorly to the broadly but shallowly impressed metanotal groove. Metanotal 
cross-ribs conspicuous dorsally, but laterally becoming confused with the strong mesopleural sculpture. 
Propodeal dorsum evenly convex in profile, rounding broadly into the declivity. Petiole node subconical, 
tapering and narrowly rounded dorsally. Anterior peduncle relatively long and subtended by a ridge-like 
ventral process which is expanded into a small lobe anteriorly. Postpetiole node smaller than petiole , with a 
steep anterior face but more broadly rounded above than the petiole node. All dorsal surfaces of head and 
body with stout conspicuous standing hairs, the promesonotum with 4 pairs. Scattered hair-pits present on 
head and body, metanotal cross-ribs conspicuous, and the mesopleuron strongly reticulate-punctate; 
sculpture otherwise absent. Head and alitrunk dark brown, gaster black. Legs conspicuously much lighter 
than alitrunk, tending to be very pale yellow or almost colourless. 

Paratype workers. TL 1-7-1-9, HL 0-39-0-42, HW 0-32-0-35, CI 79-83, SL 0-32-0-36, SI 100-109, PW 
0-22-0-23, AL 0-44-0-46 (8 measured). As holotype but maximum diameter of eye 0-21-0-24 x HW and 
with 5-6 ommatidia in longest row. With 4-5 pairs of standing hairs on the promesonotum. 

Holotype worker, Cameroun: Nkoemvon, 25. xi. 1980, no. N52 (D. Jackson) (BMNH). 

Paratypes. 5 workers with same data as holotype, and 3 workers with same locality but 6.x. 1980, no. N34 
(BMNH;MCZ). 

Non-paratypic material examined. Cameroun: Buea (B. Malkin). Gabon: Plateau d'Ipassa (J. A. 
Barra). Angola: Dundo, Carrisso Pk (L. de Carvalho). 

A conspicuous species characterized within the group with noxitum, gabrielense and strangulatum by the 
form of the clypeus, position of the eyes, length of the scapes, biconvexity of the head and strongly domed 
promesonotum. Also diagnostic of this small complex of species is the relatively long petiolar peduncel and 
subconical node, as illustrated in gabrielense (Fig. 76). 

Of these four species strangulatum has only 11 antennal segments, and gabrielense is small and lightly 
coloured. M. draxocum and noxitum are very closely related and may prove inseparable when more 
material had been amassed. Characters separating them in presently available material are listed under 
noxitum. 

Monomorium egens Forel 

(Figs 71, 82) 

Monomorium egens Forel, 1910b: 443. Holotype worker, Cameroun (Muralt) (MHN) [examined]. 
Monomorium jucundum Santschi, 1926a: 232. Syntype workers, Zaire: Luebo 16.xii. 1921 (H. 

Schouteden) (MRAC; NMB) [examined]. Syn. n. 
Monomorium longiusculum Santschi, 1926a: 237, fig. 3G. Holotype worker, Zaire: Lukuga superieur 

(Gerard) (NMB) [examined]. Syn. n. 

Worker. TL 2-0-2-5, HL 0-46-0-64, HW 0-39-0-54, CI 79-89, SL 0-33-0-47, SI 80-96, PW 0-24-0-30, 
AL 0-54-0-70 (28 measured). 



386 B. BOLTON 

Clypeal carinae moderately strongly developed, divergent anteriorly. Prominent median portion of 
clypeus relatively short, its anterior margin sometimes only shallowly concave but usually snowing an 
extensive concavity. Angles where anterior and lateral margins of median section of clypeus meet lacking 
denticles or prominent angles. Maximum diameter of eye 0- 19-0-21 x HW, the relatively small eyes with 
their posterior margins at or just in front of the midlength of the sides when seen in full-face view. Antennal 
scapes, when laid straight back from their insertions, failing to reach the occipital margin. In full-face view 
the sides of the head distinctly convex, the occipital margin broadly but shallowly concave. Pronotum 
almost or quite flat transversely when viewed from behind and slightly above. The humeral corners in this 
view conspicuous and distinctly angular, rather than broadly evenly rounded, and the dorsum of the 
pronotum separated from the sides by bluntly angular longitudinal marginations. In profile the pronotum 
flat to shallowly convex, sloping upwards posteriorly. The mesonotum convex and sloping posteriorly to 
the narrow but conspicuously impressed metanotal groove; the latter with short cross-ribs. Propodeal 
spiracle minute and pinhole-like, the dorsum of the segment shallowly convex in profile. Petiole node in 
profile bluntly subconical, with an inconspicuous narrow strip-like ventral process. Postpetiole smaller 
than petiole, lower and more broadly rounded. All dorsal surfaces of head and alitrunk with numerous 
standing hairs, the antennal scapes with long fine erect to suberect hairs. Head and body smooth and 
without sculpture except for minute hair-pits, metanotal cross-ribs and frequently (but not always) a 
narrow transverse reticulate band across the mesopleuron. Colour brown to blackish brown. 

This species, as presently constituted, is widely distributed in West and Central Africa and is quickly 
diagnosed by the construction of the pronotum, minute spiracle, small eyes and densely hairy scapes. This 
combination of characters, together with the others given above, lead me to treat all the samples listed 
below as members of a single species, but I am not truly convinced that this is correct. In some short series 
from Cameroun and Ghana the clypeus is much more shallowly concave than is usual, that is, as in Fig. 71, 
and also in the Cameroun series the propodeum is more strongly convex in profile. A single worker, also 
from Cameroun, has the head and gaster much darker in colour than the alitrunk, with colours reminiscent 
of floricola. Here again the anterior clypeal margin is almost transverse, much less concave than in egens 
holotype and most other samples, although the colours may indicate a teneral individual. Degree of 
convexity of the sides of the head varies from sample to sample and the petiole node in some is slightly 
inclined forward. Further study of egens, as it is presently understood, will be essential when more samples 
and especially longer series are available, and may lead to the recognition of two or even more species here. 

Usually egens nest in rotten wood in the soil or in fallen trunks, and forages in the wood and the 
surrounding leaf litter. More rarely the ants nest in rotten parts of standing trees, some distance above the 
ground. 

Two closely related but distinctly different species occur in Cameroun, draxocum and noxitum. These 
have not been found anywhere else in West or Central Africa and both lack the characteristic pronotal 
structure of egens. A rather more distant relative is strangulatwn, known from Uganda and Tanzania, in 
which the number of antennal segments has been reduced from 12 to 11. 

Material examined 

Ivory Coast: Banco Forest, nr Abidjan (W. L. Brown). Ghana: Atewa (D. Leston); Bunso (D. Leston); 
Asamankese (D. Leston); Enchi (D. Leston); Adeiso (D. Leston); Mepom (D. Leston); Legon (D. 
Leston); Aburi (P. Room); Afwerase (P. Room); Tafo (B. Bolton). Nigeria: Gambari (B. Bolton); 
Gambari (B. Taylor). Cameroun: no loc. (Muralt); Nkoemvon (several short series) (D. Jackson). Zaire: 
Luebo (H. Schouteden); Upper Lukuga {Gerard); Ituri Forest, Beni-Irumu (N. A. Weber). Angola: R. 
Chissanguiri (L. de Carvalho); Dundo, Carrisso Pk (no name). 

Monomorium excensurae For el stat. n. 

(Figs 61, 75) 

Monomorium oscaris var. excensurae Forel, 1915: 342. Syntype workers, South Africa: Cape Prov., 
Kentani (A. Pegler) (MHN) [examined]. 

Worker. TL 1-9-2-2, HL 0-50-0-58, HW 0-38-0-45, CI 76-79, SL 0-40-0-48, SI 104-110, PW 0-26-0-29, 
AL 0-50-0-64 (10 measured). 

Clypeal carinae close together, subparallel, usually very weakly divergent anteriorly but in some the 
carinae weakly bowed outwards to their midlengths then curving in again anteriorly. Prominent median 
portion of clypeus narrow, its anterior margin transverse to concave between the apices of the carinae and 
lacking denticles or sharp angles at the junction of its anterior and lateral margins. Maximum diameter of 



SOLENOPSIS GENUS-GROUP 387 

eye 0-20-0-23 x HW and with 5-6 ommatidia in the longest row. In full-face view the posterior margins of 
the eyes at the midlength of the sides of the head. Antennal scapes, when laid straight back from their 
insertions, just reaching or fractionally surpassing the occipital margin. Sides of head in full-face view 
evenly convex, broadest at level of hind margins of eyes; occipital margin very shallowly concave. 
Promesonotum in profile quite shallowly evenly convex, the highest point in front of the promesonotal 
midlength and on a higher level than the highest point of the propodeum. Metanotal groove impressed but 
narrow and traversed by short inconspicuous cross-ribs. Propodeal spiracle minute and pinhole-like. 
Petiole with a narrow anterior peduncle in profile, the subpetiolar process a small anteroventral lobe which 
varies in shape and size. Petiole node subconical, the anterior face much longer and more shallowly sloping 
than the posterior. Postpetiole node smaller, lower and more broadly rounded than the petiole. All dorsal 
surfaces of head and body with standing hairs, the promesonotum with 4 or 5 pairs. Body and head entirely 
lacking sculpture except for minute hair-pits and metanotal weak cross-ribs. Colour uniform yellow. 

M. excensurae belongs to the schultzei-complex and is closely related to bevisi and schultzei itself, the 
three species possessing a minute and pinhole-like propodeal spiracle. Of the three bevisi is dingy brown in 
colour and conspicuously more densely hairy than schultzei or excensurae , both of which are yellow. These 
last two are very closely related and are best separated by the slightly larger eyes and shorter scapes of 
schultzei. Apart from this the outline shape of the eye is more nearly round in excensurae , whereas in 
schultzei the longitudinal axis of the eye is more obviously longer than the vertical axis. The clypeal carinae 
of schultzei are more strongly developed and the area of clypeus between them more deeply concave, and 
the dorsum of the petiole node in dorsal view is more anteroposteriorly compressed in schultzei. 

Material examined 
South Africa: Cape Prov., Kentani (A. Pegler); Grahamstown, Beggar's Bush (W. L. Brown). 

Monomorium exchao Santschi 

(Figs 70, 77) 

Monomorium exchao Santschi, 1926a: 235. Syntype workers, South Africa: Cape Prov., Grahamstown, 
Paradise Kloof, xii.1919 (J. Hewitt) (NMB) [examined]. 

Worker. TL 1-9-2-0, HL 0-49-0-50, HW 0-37-0-38, CI 74-77, SL 0-33-0-34, SI 89-91, PW 0-24-0-25, 
AL 0-52-0-54 (3 measured). 

Clypeal carinae strongly developed and sharp, subparallel or only feebly divergent anteriorly. Apices of 
clypeal carinae meeting anterior border of clypeus mesad of the anterolateral angles of the prominent 
median section of the clypeus, not running to the angles themselves. Prominent median portion of clypeus 
with its anterior margin transverse to concave between the apices of the carinae; outside the carinae on 
each side the anterior margin meeting the lateral margin of the prominent section in an obtuse but 
conspicuous angle. Maximum diameter of eye 0-20-0-21 x HW and with 4-5 ommatidia in the longest 
row. In full-face view the eyes with their posterior margins distinctly in front of the midlength of the side, 
and the antennal scapes, when laid straight back, failing to reach the occipital margin. Sides of head 
shallowly convex in full-face view, the occipital margin relatively short and more or less transverse, only 
with the feeblest concavity across its width. Promesonotum in profile low, shallowly and evenly convex. 
Metanotal groove strongly impressed and conspicuous, the propodeum behind the groove convex and then 
sloping backwards to round broadly and evenly into the declivity so that the two surfaces form a single 
convexity. Petiole in profile bluntly conical, postpetiole smaller than petiole and rounded. All dorsal 
surfaces of head and body with standing hairs present, the promesonotum apparently with 4 pairs but all 
the syntypes appear abraded and the total count may in fact be higher. Body entirely unsculptured except 
for hair-pits and cross-ribs at the metanotal groove. Colour uniform yellow. 

M. exchao is closest related to symmotu, but the two are separable by the shape of the petiole in profile 
and the more broadly rounded outline of the propodeum in symmotu, compare Figs 77, 79. 

Material examined 
South Africa: Grahamstown, Paradise Kloof (J. Hewitt); E. Cape Prov., Hogsback (W. L. Brown). 



388 B. BOLTON 

Monomorium exiguum Forel 

Monomorium exiguum Forel, 1894a: 85. Syntype workers, Ethiopia: 'Sudabessinien' (Ilg) (MHN) 

[examined]. 
Monomorium (Mitara) exiguum var. bulawayensis Forel, 1913c: 217. Syntype workers, Zimbabwe: 

Bulawayo, 20.vii.1913, no. 179 (G. Arnold) (BMNH; MHN; MCZ) [examined]. Syn. n. 
Monomorium (Mitara) faurei Santschi, 1915: 260, fig. 10. Syntype workers, Gabon: Samkita (Faure) 

(NMB; MRAC) [examined]. Syn. n. (provisional). 
Monomorium (Mitara) exiguum v.flavescens Forel, 1916: 418. Syntype workers, Zaire: St Gabriel (Kohl) 

(MHN) [examined]. Syn. n. (provisional). 

Worker. TL 1-5-1-7, HL 0-36-0-42, HW 0-28-0-32, CI 74-80, SL 0-22-0-27, SI 74-84, PW 0-17-0-21, 
AL 0-36-0-44 (40 measured). 

Clypeal carinae present but quite weakly developed, widely separated and distinctly divergent anteriorly 
and with a tendency to peter out before reaching the anterior clypeal margin. Median portion of clypeus 
prominent but lacking sharp angles or denticles where its anterior and lateral margins meet. Maximum 
diameter of eye 0- 19-0-22 x H W. Eyes in profile consisting of an outer ring of ommatidia which encloses a 
single longitudinal row of only 2-3 ommatidia; rarely with another one or two ommatidia within the ring. 
In full-face view the eyes conspicuously in front of the midlength of the sides. Antennae with 11 segments. 
Antennal scapes, when laid straight back from their insertions, failing to reach the occipital margin. 
Promesonotum shallowly convex in profile, the metanotal groove shallowly impressed but with distinct 
short cross-ribs. Propodeal dorsum and declivity forming a single rounded convexity; propodeal spiracle 
minute and pinhole-like. Petiolar peduncle short and stout, with a small anteroventral process. Node of 
petiole low-subconical in profile, broad basally and tapering rapidly to a narrow but bluntly rounded apex. 
Postpetiole smaller than petiole , lower and much more broadly convex dorsally . All dorsal surfaces of body 
with standing hairs, the pronotum with a pair on the anterior margin between the humeral pair. In total the 
promesonotum usually with 4 pairs of standing hairs but sometimes a fifth pair may be present. Entirely 
lacking sculpture except for the metanotal cross-ribs, or rarely with some faint shagreening on the 
mesopleuron. Colour very variable, from clear yellow to uniform dark brown, frequently with a pair of 
darker patches or a darker band apically on the first gastral tergite. 

Without doubt the name exiguum, as presently constituted, conceals more than one valid species, but a 
very detailed analysis of much more material than is currently available will be necessary to split up the 
mass. Particularly interesting is the occurrence of both alate and apterous females among the Ghanaian 
samples listed below. Almost certainly this indicates that two species are present in Ghana and workers 
associated with the apterous females closely match the type-series of flavescens. Unfortunately females 
from the rest of the range are utterly unknown so no comparisons can be accurately made. 

The species closest to exiguum as defined here is vaguum, but this is easily distinguished by the presence 
in the latter of a conspicuous clump of 4 or more pairs of hairs on the pronotum. 

Material examined 

Ivory Coast: 40 km W. Abidjan (W. L. Brown). Ghana: Kibi (D. Leston); Mampong (P. Room); Boku 
(C. A. Collingwood); Pankese (C. A. Collingwood); Legon (D. Leston); Tafo (B. Bolton); Tumu (P. 
Room). Nigeria: Gambari (B. Bolton); Gambari (B. Taylor). Cameroun: Nkoemvon (D. Jackson). 
Gabon: Samkita (Faure). Zaire: St Gabriel (Kohl). Ethiopia: 'Sudabessinien' (Ilg). Kenya: Tana R., Kora 
(Collins & Ritchie). Zimbabwe: Bulawayo (G. Arnold); Sawmills (G. Arnold), Victoria Falls (G. Arnold). 

Monomorium fasciatum Santschi nomen dubium 

Monomorium fasciatum Santschi, 1920Z?: 10, figs lc-e. Holotype worker, Kenya: Kilimanjaro (Reichens- 
perger) (NMB) [not seen]. 

Dr Cesare Baroni Urbani (NMB) informs me that only the gaster of the holotype worker remains on the 
mount. From Santschi's original description and figures fasciatum undoubtedly belongs to the schultzei- 
complex and further belongs with those members of the complex in which the propodeal spiracle is 
relatively large. In East Africa these include arboreum, crawleyi and kineti. However, none of these three 
match Santschi's description and figures sufficiently well to confirm an identity, and fasciatum must remain 
as a nomen dubium. 



SOLENOPSIS GENUS-GROUP 389 

Monomorium fastidium sp. n. 

Holotype worker. TL 1 -4, HL 042, HW 0-33, CI 79, SL 0-27, SI 82, PW 0-20, AL 0-42. 

Clypeal carinae distinctly developed, divergent anteriorly, reaching the anterior margin but not 
terminating in denticles or angular projections. In full-face view the median portion of the clypeus 
prominent and the anterior border of the prominence more or less transverse. Maximum diameter of eye 
0-21 x HW. In profile the eye longer than high and consisting of an outer ring of ommatidia enclosing a 
single longitudinal row of only 3 ommatidia. In full-face view the eye conspicuously in front of the 
midlength of the sides of the head. Antennae with 1 1 segments. Antennal scapes, when laid straight back 
from their insertions, failing to reach the occipital margin. Head capsule in full-face view broadest 
posteriorly, the sides evenly and gradually narrowing anteriorly and the eyes situated in front of the 
broadest part of the head. In profile the ventral surface of the head convex, the convexity only shallow but 
noticeably greater than the convexity of the cephalic dorsum immediately behind eye-level. Promesono- 
tum in profile not strongly convex, sloping very shallowly to the distinctly impressed and relatively broad 
metanotal groove; the latter with conspicuous cross-ribs. Propodeum highest immediately behind the 
metanotal groove then falling away posteriorly in an even, smoothly convex curve, without differentiation 
into dorsum and declivity. Propodeal spiracle minute and pinhole-like. Anterior peduncle of petiole short 
and stout, with a small lobulate ventral process. Petiole node with anterior face longer and somewhat more 
shallowly sloped than posterior face; the node narrowly but bluntly rounded above. Postpetiole smaller 
and slightly lower than petiole, much more broadly rounded dorsally. All dorsal surfaces of head and body 
with standing hairs, the promesonotum with only 3 pairs. Anterior margin of pronotum without a pair of 
standing hairs between those at the humeri. Unsculptured except for the metanotal cross-ribs. Colour 
uniform dull pale yellow. 

Paratype workers. TL 1-4, HL 0-42-0-43, HW 0-32-0-33, CI 76-79, SL 0-26-0-28, SI 81-85, PW 
0-20-0-21, AL 0-42-0-44 (10 measured). As holotype but some paratypes have a fourth promesontal pair 
of standing hairs. 

Holotype worker, South Africa: E. Cape Prov., Walmer nr Port Elizabeth, 3.iii.l969, eucalypt litter, 
M374 (W. L. Brown) (MCZ). 
Paratypes. 10 workers and 5 alate females with same data as holotype (MCZ; BMNH). 

A minute yellow species close to and slightly larger than mictilis, but lacking the depressed head capsule 
of that species and having the promesonotum somewhat more convex. Apart from this the head in mictilis 
tends to be somewhat narrower (CI 72-76 as opposed to CI 76-79 in fastidium) and slightly different in 
shape. Whereas in fastidium the head in full-face view is broadest behind and narrows anteriorly, the head 
in mictilis is broadest immediately behind the eyes and gradually narrows both anteriorly and posteriorly 
from this point. 

Monomorium firmum Santschi 
(Fig. 67) 

Monomorium firmum Santschi, 1926a: 231. Syntype workers, Zimbabwe: Vumba Mts, 6000 ft (1830 m), 
Cloudlands 6-17. iv. 1923 (G. Arnold) (BMNH; NMB) [examined]. 

Worker. TL 2-6-2-8, HL 0-58-0-66, HW 0-46-0-54, CI 79-83, SL 0-50-0-56, SI 100-109, PW 0-30-0-33, 
AL 0-70-0-76 (10 measured). 

Clypeal carinae conspicuous, relatively close together, feebly divergent anteriorly and sometimes the 
carinae broken or interrupted at about their midlength. Space between the clypeal carinae shallowly 
transversely concave. Anterior margin of narrow prominent median section of clypeus weakly concave, the 
anterior and lateral margins of this section separated by blunt angles, without projecting denticles. 
Maximum diameter of eye 0-20-0-22 x HW and with 6-7 ommatidia in the longest row. With the head in 
full-face view the eyes close to the midlength of the sides, usually the posterior margins of the eyes at or 
even slightly behind the midlength of the sides. Antennal scapes, when laid straight back from their 
insertions, reaching or slightly surpassing the occipital margin. Sides of head evenly shallowly convex in 
full-face view and the occipital margin shallowly convex or the median area more or less flat. Promesono- 
tum in profile a low convexity, descending behind to the broad impressed metanotal groove which is 
traversed by long strong cross-ribs. Propodeal spiracle large and conspicuous. Petiole node in profile 
relatively low, broadly subconical and with both anterior and posterior faces weakly convex. Subpetiolar 



390 B. BOLTON 

process a conspicuous lobe. Postpetiole lower than petiole, smaller and more broadly rounded in profile. 
All dorsal surfaces of head and body with numerous standing hairs, the promesonotum with more than 8 
pairs. Mostly unsculptured and shining except for scattered hair-pits, but the metanotal groove cross- 
ribbed and the mesopleuron in some with traces of weak reticulate sculpture. Colour yellow. 

Known only from the type-series, this relatively large yellow species is a conspicuous member of the 
schultzei-comp\ex. It is closest related to vecte, also known from Zimbabwe, the two together being 
distinguished from the remaining schultzei-complex members which have relatively large propodeal 
spiracles by their dense pilosity. Of all schultzei-complex members in which the metanotal groove is broad 
and traversed by long conspicuous cross-ribs, and the propodeal spiracle is large, only firmum and vecte 
have 8 or more pairs of hairs on the promesonotal dorsum . Differences separating the two are noted under 
vecte. 

Material examined 
Zimbabwe: Vumba Mts (G. Arnold). 

Monomorium floricola (Jerdon) 

Attafloricola Jerdon, 1851: 107. Syntype workers, India. [No types known to exist.] 

Monomorium poecilum Roger, 1863a: 199. Syntype workers, female, Cuba (probably in MNHU) [not 

seen]. [Synonymy by Emery, 1894: 151.] 
Monomorium cinnabari Roger, 1863a: 199. Syntype workers, Cuba (probably in MNHU) [not seen] 

[Provisional synonymy by Wheeler, 1913: 486.] 
Monomorium specularis Mayr, 1866: 509. Syntype workers, West Samoa: Upolu (NMV) [not seen]. 

[Synonymy by Mayr, 1878: 671.] 
Monomorium floricola (Jerdon) Mayr, 1878: 671. 
Monomorium impressum Smith, 1876: 447. Syntype females, male, Rodriguez I. (Gulliver) (BMNH) 

[examined]. Syn. n. 
Monomorium (Monomorium) angusticlava Donisthorpe, 1947: 189. Paratype workers, New Guinea: 

Maffin Bay, 27. vi. 1944 and viii.1944 (E. S. Ross) (BMNH) [examined]. Syn. n. 

Note on synonymy. The Japanese species M. intrudens Smith (1874) was synonymised with floricola by 
Wheeler (1906: 310), acting on a note which he received from Emery. Neither author had seen the 
intrudens holotype (in BMNH) and were working from Smith's original description. Examination of the 
holotype shows that the synonymy of intrudens under floricola was incorrect and that the two are separate 
species. Comparison of intrudens holotype with fresh Japanese material of Monomorium shows it to be the 
senior synonym of M. nipponense Wheeler (1906), the holotype corresponding well with nipponense 
material collected by Masahiro Tanaka at Yoshida-yama, Kyoto. Thus M. intrudens Smith is removed 
from the synonymy of floricola, reinstated as a valid species, and is the senior synonym of M. nipponense 
Wheeler. Some ecological work on this species has recently been carried out by Ochi (1983). 

Worker. TL 1-7-2-0, HL 0-42-0-48, HW 0-32-0-37, CI 75-80, SL 0-29-0-34, SI 86-94, PW 0-20-0-24, 
AL 0-40-0-50 (30 measured). 

Anterior margin of prominent median portion of clypeus usually shallowly concave between the apices 
of the clypeal carinae; sometimes more or less transverse. Clypeal carinae quite sharply developed, 
relatively widely separated and feebly divergent anteriorly. Anterior and lateral borders of prominent 
median portion of clypeus separated by an angle. Maximum diameter of eye 0-21-0-24 x HW. In profile 
the eye consisting of an outer ring of ommatidia which encloses a single inner longitudinal row. Eye always 
distinctly longer than high and the encircled row with 2-4 (usually 3) ommatidia. Individuals in several 
samples show an extra 1-2 ommatidia above or below the longitudinal row, but this is rare. In full-face view 
the eyes in front of the midlength of the sides. Antennal scapes, when laid straight back from their 
insertions, failing to reach the occipital margin. Promesonotum shallowly convex in profile, sloping 
posteriorly to the shallowly impressed metanotal groove; in a few samples the metanotal groove is virtually 
unimpressed. Dorsum of propodeum on a slightly lower level than the promesonotum, the dorsum 
rounding broadly and evenly into the declivity. Node of petiole in profile bluntly subconical, the ventral 
process of the peduncle confluent posteriorly with the ventral margin of the node so that the ventral outline 
of the petiole node is flat or nearly so; there is no conspicuous convex bulge of the margin behind the 
termination of the subpetiolar process. Node of postpetiole in profile about the same size as that of the 
petiole or slightly smaller; the postpetiole node more broadly rounded than that of the petiole. All dorsal 
surfaces of the head and body with standing hairs present; the promesonotum with 5 pairs and the 



SOLENOPSIS GENUS-GROUP 391 

propodeum with a single pair. Smooth and shining, unsculptured except for the metanotal cross-ribs and 
sometimes a little reticular sculpture on the pleurae. Colour variable but colour pattern characteristic. 
Head and gaster dark brown to black, the gaster sometimes slightly darker than the head. Alitrunk yellow 
to brown, usually strongly contrasting with the head and only rarely almost as dark in colour, generally 
much lighter than the head. Petiole and postpetiole yellow and usually lighter than the alitrunk or the same 
colour as the alitrunk. 

An extremely successful pantropical tramp-species, floricola has been widely dispersed by human 
commercial activity. In temperate zones it can establish itself in hothouses and other constantly heated 
buildings, and recently it has been reported nesting in centrally heated blocks of flats in England. A 
bibliography of the species and its North American distribution are given by Krombein et al. (1979). The 
Neotropical distribution of floricola is given by Kempf (1972) and its occurrence in Polynesia is 
documented by Wilson & Taylor (1967). 

In the Afrotropical fauna floricola shares the character combination of 12-segmented antennae and eye 
form as described above with only 5 other species. None of these show the colour pattern of floricola and all 
have antennal scapes which are relatively shorter, see comparative measurements under rotundatum. 

Material examined 

Afrotropical region. Ghana: Tafo (B. Bolton); Tafo (C A. Collingwood); Legon (D. Leston); Kibi (D. 
Leston). Togo: Tove (B. Dufour). Nigeria: Gambari (B. Bolton). Cameroun: Nkoemvon (D. Jackson). 
Tanzania: Zanzibar, Chwaka (M. J. Way). 

Other regions. India: Bangalore (T. M. Ali); NE India (5. P. Kurl). Sri Lanka: noloc. (H. S. Andrewes); 
Colombo (A. Baur). Burma: Bhamo (Bingham). Andaman Is. (G. Rogers). Mauritius: Rose Hill (R. 
Mamet); Beau Bassin (R. Mamet). Aldabra: South I. (B. Cogan &A. Hutson). Chagos Archipelago: Diego 
Garcia (A. M. Hutson). Rodriguez I. (coll. F. Smith). Seychelle Is.: Little Sister I. (U. Muller), Cousin I. 
(G. M. Bathe). Japan: Iriomote, Mt Sonai-dake (A/. Tanaka). East Malaysia: Sarawak (Haviland). 
Indonesia: Sulawesi, Dumoga Bone N.P. (P. Hammond); Dumoga Bone N.P. (N. Stork). Papua New 
Guinea: Kokoda (L. Cheesman); Cyclops Mts, Sabron (L. Cheesman); Maffin Bay (E. S. Ross). Solomon 
Is.: New Georgia (H. T. Pagden); Tulagi (R. A. Lever); Guadalcanal (E. S. Brown). New Hebrides: 
Malekula (L. Cheesman); Santo (L. Cheesman); Eromanga (L. Cheesman). Samoa: Upolu, Apia (Buxton 
& Hopkins); Apia (N. Swale); Apia (C. L. Edwards); Tutuila (Swezey & Wilder). Fiji Is.: Nabavatu (T. H. 
C. Taylor); Taveuni, Waiyevi (H. S. Evans). Hawaii: Oahu, Waianae (N. L. H. Krauss). Gilbert Is.: S. 
Tarawa (P. Maddison). Antilles: St Lucia (no coll. name). West Indies: Grenada (H. H. Smith). Puerto 
Rico: Mayaquez (M. R. Smith). Guiana: Georgetown (G. E. Bokin). Brazil: S.P., Ribeirao Preto (W. 
Hamilton). Colombia: Gorgona I. (L. E. Cheesman). U.S.A.: Florida, Fort Mayers (W. M. Barrows). 
Great Britain: Wales, Bangor (A. J. Rundle); England, London (no coll. name). 

Monomorium fugelanum sp. n. 

(Fig. 88) 

Holotype worker. TL 1-8, HL 0-50, HW 0-39, CI 78, SL 0-36, SI 92, PW 0-25, AL 0-52. 

Clypeal carinae strongly developed, raised and markedly divergent anteriorly; the carinae running to the 
anterior margin. Prominent median portion of clypeus with a transverse anterior margin, flanked by a pair 
of low triangular projections which distinctly separate the anterior and lateral margins of the median 
clypeus. Eyes relatively large, 0-26 x HW and with 7 ommatidia in the longest row. In full-face view the 
posterior margins of the eyes are conspicuously in front of the midlength of the sides of the head. Antennal 
scapes, when laid straight back from their articulations, just failing to reach the occipital margin. Sides of 
head behind eyes very shallowly convex in full-face view, extremely feebly convergent posteriorly. 
Occipital margin broad and more or less transverse, with only the merest trace of concavity towards the 
centre. Promesonotal dorsum evenly shallowly convex in profile, sloping posteriorly to the narrow and 
shallowly impressed metanotal groove. Metanotal cross-ribs short and inconspicuous and the propodeal 
spiracle minute, pinhole-like. Propodeal dorsum a long shallowly convex slope which rounds very broadly 
and evenly into the short declivity, the two surfaces not distinctly separated. Node of petiole high and 
narrow in profile, the anterior peduncle with a small lobate ventral process. Postpetiole smaller than 
petiole, scarcely broader but lower, more broadly rounded above and with a long vertical anterior face. All 
dorsal surfaces of head and body with standing hairs, the promesonotum with 5 pairs. Sculpture absent 
except for scattered minute hair-pits and feeble metanotal cross-ribs. Colour yellow. 



392 B. BOLTON 

Paratype workers. TL 1-7-1-8, HL 0-48-0-50, HW 0-36-0-39, CI 74-78, SL 0-33-0-36, SI 92-95, PW 
0-22-0-26, AL 0-48-0-52 (6 measured). Maximum diameter of eye 0-26-0-28 x HW. Asholotype. 

Holotype worker, Botswana: Maxwee, mopane woodland, 19. v. 1976, No. 41 (A. Russell-Smith) 
(BMNH). 
Paratypes. 10 workers with same data as holotype (BMNH; MHN; MCZ). 

The closest relatives of fugelanum, and their separations, are discussed under altinode. 

Monomorium gabrielense Forel stat. n. 

(Fig. 76) 

Monomorium rhopalocerum var. gabrielensis Forel, 1916: 418. Syntype workers, female, Zaire: St 
Gabriel {Kohl) (MHN) [examined] . 

Worker. TL 1-5-1-6, HL 0-38-0-40, HW 0-30-0-32, CI 78-84, SL 0-30-0-31, SI 95-100, PW 0-19-0-20, 
AL 0-42-0-44 (10 measured). 

Clypeal carinae close posteriorly, moderately divergent anteriorly and reaching the anterior margin. 
Prominent median portion of clypeus narrow, the anterior margin between the apices of the carinae 
shallowly concave. Anterior and lateral margins of median portion of clypeus separated by an angle, 
without projecting denticles. Eyes relatively small, their maximum diameter 0-19-0-22 x HW and with 5 
ommatidia in the longest row. With the head in full-face view the eyes close to the midlength of the sides; 
usually the posterior margins of the eyes on the midline. Antennal scapes, when laid straight back from 
their insertions, slightly exceeding the occipital margin. In full-face view the sides behind the eyes and the 
occipital margin usually forming a single even convexity, but in a few workers a minute mid-occipital 
depression may be present. In profile the dorsal and ventral surfaces of the head distinctly biconvex. 
Promesonotum in profile smoothly and evenly convex, sloping posteriorly to the shallowly impressed 
metanotal groove, highest point of promesonotal curve on a conspicuously higher level than the 
propodeum. Cross-ribs of metanotal groove short and inconspicuous, the propodeal spiracle large and 
easily visible. Propodeal dorsum highest just behind metanotal groove, sloping posteriorly to the obtuse 
rounded angle which separates dorsum from declivity; the two surfaces not forming a smooth even curve. 
Petiole node in profile subconical and narrowly rounded above, the subpetiolar process a narrow and 
inconspicuous laminar strip. Postpetiole node smaller, lower and more broadly convex than petiole node in 
profile. All dorsal surfaces of head and body with standing hairs present, the promesonotum with 4-5 pairs, 
and many hairs on head and first gastral tergite blunt or truncated apically. Sculpture consisting only of 
scattered hair-pits, metanotal cross-ribs, and a band of fine reticulation traversing the mesopleuron; 
otherwise entirely smooth and shining. Colour yellow, the gaster with a brownish tint. 

The minute pale gabrielense is close to noxitum, draxocum and strangulatum. The last named is 
immediately separable as it has only 11 antennal segments, as opposed to 12 in the remainder. Both 
noxitum and draxocum are brown to black in colour, much darker than gabrielense, and both are larger, 
though only slightly so in draxocum. Comparative dimensions are as follows. 





HW 


SL 


PW 


gabrielense 


0-30-0-32 


0-30-0-31 


0-19-0-20 


draxocum 


0-32-0-35 


0-32-0-36 


0-22-0-23 


noxitum 


0-37-0-40 


0-39-0-42 


0-24-0-27 



Material examined 
Gabon: He aux Singes (/. A. Barra). Zaire: St Gabriel {Kohl). 

Monomorium guillarmodi Arnold 

Monomorium {Lampromyrmex) guillarmodi Arnold, 1946: 63, figs 15, 15a. Syntype workers, female, 
Lesotho: Mamathes, 5.ix.l942 (C. J acot-Guillarmod) (SAM) [examined]. 

Worker. TL 1-6-1-7, HL 0-40-0-41, HW 0-32-0-33, CI 78-80, SL 0-23-0-24, SI 72-75, PW 0-20-0-21, 
AL 0-38-0-42 (3 measured). 
Basal (fourth) tooth of the smooth mandibles less than half the size of the third tooth. Median portion of 






SOLENOPSIS GENUS-GROUP 393 



anterior clypeal margin transverse or with a shallow and narrow central indentation. Maximum diameter of 
eye 0-15—0-17 x HW and with 5 ommatidia in the longest row. Peripheral ring of ommatidia enclosing 
more than one longitudinal row. Antennae with 11 segments, the scapes relatively short (SI < 80), failing 
to reach the occipital margin when laid straight back from their insertions. In full-face view the sides of the 
head evenly shallowly convex and the occipital margin almost transverse, with only the slightest 
indentation centrally. Median portion of clypeus prominent and with sharply defined anterolateral angles, 
with fine but conspicuous carinae. Posterior margins of eyes in front of the midlength of the sides in 
full-face view. In profile the anterior curved declivity of the pronotum is followed by a flat promesonotal 
surface which terminates at the narrowly and shallowly impressed metanotal groove. Behind the metanotal 
groove the propodeal dorsum is shallowly convex and slopes posteriorly to its bluntly rounded junction 
with the declivity, the two surfaces meeting at the level of the pinhole-like spiracle. Petiole node markedly 
larger than postpetiole node in profile, the dorsal outline of the latter low and evenly domed-convex. 
Petiole node in profile with a short anterior peduncle which is subtended by a narrow ridge-like 
anteroventral process; ventral surface of petiole below the highest point of the node is broadly convex, the 
convexity projecting ventrally more than does the subpetiolar process. Petiole node low and bluntly 
triangular, narrowly rounded above. In dorsal view both nodes of approximately equal width, both slightly 
broader than long. Entire body unsculptured, smooth and shining except for narrow cross-ribbing at the 
metanotal groove. Dorsum of head with 1-2 pairs of standing hairs along the occipital margin and a pair at 
the frontal lobes, but the head between these lacking standing hairs. Dorsal alitrunk without standing 
hairs. Petiole and postpetiole each with a single pair of backward directed hairs and gaster with sparse 
similar pilosity. Colour glossy light to medium brown. 

Immediately isolated from all other Afrotropical Monomorium in which the antennae have 1 1 segments 
by its lack of standing hairs anywhere on the dorsal alitrunk and their paucity elsewhere on the body. 

Material examined 
Lesotho: Mamathes (C. Jacot-Guillarmod). 

Monomorium holothir sp. n. 

Holotype worker. TL 1-9, HL 0-50, HW 0-36, CI 72, SL 0-34, SI 94, PW 0-24, AL 0-48. 

Clypeal carinae sharply developed, conspicuously elevated and crest-like, divergent anteriorly and 
reaching the anterior margin at a pair of short low triangular projecting angles. These projecting angles 
separate the transverse to feebly concave anterior margin of the prominent median portion of the clypeus 
from its lateral margins. Eyes relatively large, their maximum diameter 0-30 x HW and with 8-9 
ommatidia in the longest row. In profile the maximum diameter of the eye distinctly greater than the 
distance between the anteriormost point of the eye and the nearest point of the mandibular articulation. In 
full-face view the posterior margins of the eyes slightly in front of the midlength of the sides. Antennal 
scapes, when laid straight back, failing to reach the occipital margin. With the head in full-face view the 
sides shallowly convex behind the eyes, scarcely converging posteriorly until close to the occipital corners, 
then rounding into the broad and moderately concave occipital margin. Head in profile conspicuously 
dorsoventrally flattened, the ventral surface more convex than the dorsal. Promesonotal dorsum evenly 
shallowly convex in profile, sloping posteriorly to the narrow and feebly impressed metanotal groove. 
Metanotal cross-ribs short and inconspicuous, the propodeal spiracle small and pinhole-like. Propodeal 
dorsum evenly sloping, the posterior third more strongly sloping than the anterior two-thirds but without 
strongly differentiated dorsal and declivous faces. Petiole node high and narrowly subconical, narrowly 
rounded above, the overall shape and ventral process very similar to that of katir (Fig. 74). All dorsal 
surfaces of head and body conspicuously hairy, the promesonotum somewhat abraded but with about 8 
pairs of standing hairs. Sculpture absent except for scattered hair-pits and short metanotal cross-ribs. 
Colour yellow to light brownish yellow. 

Paratype workers. TL 1-8-1-9, HL 0-48-0-50, HW 0-36-0-37, CI 74-75, SL 0-33-0-34, SI 92, PW 
0-22-0-24, AL 0-46-0-48 (2 measured). Maximum diameter of eye 0-30-0-32 x HW; otherwise as 
holotype. 

Holotype worker, Kenya: L. Baringe, l.xii.1983 (/. Darlington) (BMNH). 
Paratypes. 2 workers with same data as holotype (BMNH; MCZ). 

This small yellowish large-eyed species is superficially very similar to the Namibian katir, but is much 
more densely hairy, has relatively somewhat smaller eyes and more sharply developed clypeal carinae, and 



394 B. BOLTON 

has the head more strongly dorsoventrally flattened. Other related large-eyed species, which are darker in 
colour, are discussed under balathir. 

Monomorium inquietum Santschi 

Monomorium inquietum Santschi, 1926a: 233, fig. 3D. Syntype workers Zaire: Haut Uele, Moto, 1920 
(L. Burgeon) (NMB ; MRAC) [examined] . 

Worker. TL 1-7-1-8, HL 0-45-0-46, HW 0-38, CI 83, SL 0-29-0-30, SI 76-79, PW 0-21-0-22, AL 
0-46-0-47 (2 measured). 

Anterior clypeal margin without a differentiated prominent median section with discrete anterior and 
lateral borders; instead the anterior clypeal margin broadly and quite evenly convex between the inner 
points of the mandibular insertions. Clypeal longitudinal carinae vestigial to absent. Eyes small, 0-16 x 
HW and with 4-5 ommatidia in the longest row. Eyes consisting of an outer ring of ommatidia which 
encloses a single short longitudinal ommatidial row. With the head in full-face view the eyes conspicuously 
far in front of the midlength of the sides, and the scapes, when laid straight back from their insertions, very 
obviously failing to reach the occipital border. SI < 80. Occipital margin very broad, evenly shallowly 
concave across its width. Sides of head shallowly convex. Dorsal outline of promesonotum shallowly 
convex and low, only slightly higher than the propodeum. Mesonotum sloping evenly to the feebly 
impressed metanotal groove, without a posterior section which is suddenly downcurved or more steeply 
sloping than the remainder. Propodeum with a small spiracular orifice, the dorsal outline of the propodeum 
convex in profile, the dorsum rounding broadly and evenly into the declivity. Petiole node in profile low 
and broadly subconical, narrowly rounded above. Subpetiolar process a low keel, semitranslucent. 
Postpetiole low and very rounded in profile, the size of the postpetiole only slightly less than that of the 
petiole. Standing hairs sparsely present on all dorsal surfaces, the promesonotum with 4 pairs, the 
propodeum with a single pair. Except for hair-pits and short cross-ribs at the metanotal groove, the entire 
body is unsculptured and smooth. Colour uniform glossy brown, the gaster slightly darker in shade than the 
head and alitrunk. 

Known only from two syntypes collected in Zaire, this small species is conspicuous by its combination of 
uniformly dark colour, small eyes, and clypeal structure. The form of the eye is the same in only five other 
species occurring in sub-Saharan Africa. Of these sryetum has only a single pair of hairs on the dorsal 
alitrunk and floricola has much longer scapes (SI 86-94). The remaining three, trake, rotundatum and 
shilohense, are mostly or entirely yellow in colour, and the last named has relatively large eyes 
(0-23-0-24 x HW). Comparative measurements of the six species are given under rotundatum. 

Material examined 
Zaire: Haute Uele, Moto (L. Burgeon). 

Monomorium iyenasu sp. n. 

Syntype workers TL ca. 3-5, HL 0-84-0-86, HW 0-72-0-74, CI 86, SL 0-54, SI 73-75, PW 0-46-0-52, AL 
0-94-1-02 (3 measured). 

Clypeal carinae weakly developed and only poorly defined, widely divergent anteriorly. Prominent 
median portion of clypeus with its anterior margin strongly concave, the concavity bounded on each side by 
a blunt obtusely angled projection of the margin. Eyes relatively small, 0-19 x HW and with 8-9 
ommatidia in the longest row. In full-face view the eyes distinctly in front of the midlength of the sides but 
their posterior margins close to the midlength. Antennal scapes relatively short (SI<80), when laid 
straight back from their insertions conspicuously failing to reach the occipital margin. Sides of head 
shallowly convex, converging anteriorly in front of the eyes and posteriorly behind them in full-face view. 
Occipital margin broadly but shallowly concave across almost its entire width. With the head in profile the 
outline biconvex, the ventral surface somewhat more strongly convex than the dorsum, the deepest point 
of the head occurring just behind the level of the eye. Promesonotal dorsum evenly convex, on a much 
higher level than the propodeum, and sloping posteriorly to the narrowly but deeply impressed metanotal 
groove. Metanotal cross-ribs strong and conspicuous both dorsally and laterally. Propodeal spiracle large 
and dominating the side of the sclerite. Propodeal dorsum sloping steeply posteriorly, rounding bluntly 
into the near-vertical declivity. Petiole node high and subconical in profile, narrowly rounded above. 
Subpetiolar process a narrow anteroventral rim or strip below the peduncle. Postpetiole much more 
broadly rounded dorsally than petiole in profile, somewhat anteroposteriorly compressed and lower than 
the petiole. All dorsal surfaces of head and body very densely hairy, the promesonotum with 20 or so pairs 
of standing hairs. Head dorsally with numerous conspicuous hair-pits. Remainder of body with less 



SOLENOPSIS GENUS-GROUP 395 

obvious hair-pits dorsally but otherwise unsculptured except for the metanotal cross-ribs and some faint 
metapleural striation. Colour predominantly yellowish brown, the cephalic dorsum and apical half of the 
gaster darker in shade than the remainder. In two of the syntypes the propodeal dorsum is as dark as the 
head. 

Syntype workers, Tanzania: Shinyanga, no further data (O. W. Richards) (BMNH). 

This very distinctive species is described from three damaged workers, mounted on a single pin. The 
upper and middle specimens are lacking the post-petiole and gaster, the lower specimen is lacking its head. 
Because of this damage the three have been described collectively and are treated as a syntypic series. 

Perhaps the most easily recognized species of this group in the Afrotropical region , iyenasu lacks obvious 
relatives and appears out of place as regards the remainder of the regional Monomorium fauna. The 
combination of large size, short scapes, dense pilosity, relatively small eyes and large propodeal spiracle 
render iyenasu immediately recognizable. 

Monomorium katir sp. n. 

(Figs 72, 74) 

Holotype worker. TL 1-9, HL 0-50, HW 0-38, CI 76, SL 0-34, SI 89, PW 0-25, AL 0-50. 

Clypeal carinae well developed, distinctly divergent anteriorly and terminating in a pair of weakly salient 
but acute angles on the anterior margin, these prominent angles separating the shallowly concave anterior 
margin of the median projecting portion of the clypeus from its sides. Eyes relatively very large, their 
maximum diameter 0-37 x HW and with 7-8 ommatidia in the longest row. In profile the maximum 
diameter of the eye is almost two times greater than the distance separating the anteriormost point of the 
eye from the nearest point of the mandibular articulation. In full-face view the eyes in front of the 
midlength of the sides, their posterior margins approximately at the midlength. Antennal scapes, when laid 
straight back from their insertions, failing to reach the occipital margin. Sides of head in full-face view 
widest at the eyes, shallowly convex and weakly convergent posteriorly. Occipital margin almost 
transverse, with only the faintest hint of concavity. Head in profile somewhat dorsoventrally flattened, the 
ventral surface less convex than the dorsal. Promesonotum shallowly convex in profile, sloping posteriorly 
to the narrow and shallowly impressed metanotal groove. Metanotal cross-ribs short and inconspicuous, 
the propodeal spiracle small. Petiole node high and narrow in profile, narrowly rounded above. Anterior 
peduncle of petiole short and stout, the ventral process conspicuous. Postpetiole node smaller lower and 
more broadly rounded than the petiole. Dorsal surfaces of body only sparsely hairy, the promesonotum 
with only 3 pairs of standing hairs, but all dorsal surfaces with standing hairs present. Sculpture absent 
except for minute scattered hair-pits, weak metanotal cross-ribs and some vestigial traces on the 
mesopleuron. Colour glossy light brownish yellow, the head and gaster slightly darker in shade than the 
alitrunk. 

Paratype workers. TL 1-7-1-9, HL 0-48-0-51, HW 0-35-0-38, CI 72-76, SL 0-32-0-34, SI 89-94, PW 
0-23-0-25, AL 0-44-0-50 (12 measured). As holotype but maximum diameter of eye 0-35-0-38 x HW. 
Some workers have only two pairs of promesonotal standing hairs, the posteriormost pair being absent, 
and the subpetiolar process may be smaller and less conspicuous than is indicated in Fig. 74. 

Holotype worker, Namibia: Namib desert, 15° 18' E, 23° 06' S, pitfall sample P3, 1984 (A. C. Marsh) 
(BMNH). 

Paratypes. 11 workers with same data as holotype; 6 workers with same data but 15° 24' E, 23° 06' S, 
sample P4 (BMNH; MHN; MCZ). 

The relatively very large eyes of this small species and its reduced dorsal pilosity render it easily 
recognizable. For discussion of related species see under balathir. 

Monomorium kelapre sp. n. 

Holotype worker. TL 1-9, HL 0-50, HW 0-40, CI 80, SL 0-32, SI 80, PW 0-24, AL 0-52. 

Prominent median portion of clypeus with its anterior margin evenly broadly convex. Clypeal carinae 
vestigial, low rounded and poorly defined, fading out anteriorly. Maximum diameter of eye 0-20 x HW 
and with 6 ommatidia in the longest row. In full-face view the eyes distinctly in front of the midlength of the 
sides. Antennal scapes, when laid straight back from their insertions, failing to reach the occipital margin, 



396 B. BOLTON 

the scapes relatively short (SI 80). Outline shape of head very similar to that of boerorum (Fig. 63), the 
occipital margin broad and broadly shallowly concave. Promesonotum in profile convex anteriorly, the 
highest point well in front of the midlength, on the pronotum itself rather than at the junction of pronotum 
and mesonotum. Pronotum behind the highest point and mesonotum forming a posteriorly sloping, almost 
flat surface to the metanotal groove. Posterior fraction of mesonotum suddenly downcurved to the narrow 
but deeply impressed metanotal groove, which is narrowly U-shaped. Metanotal cross-ribs short but 
conspicuous. Propodeal dorsum convex and sloping posteriorly, highest immediately behind the metanotal 
groove; rounding broadly and evenly into the declivity through a steep curve. Propodeal spiracle very 
large, dominating the side of the sclerite. Petiole with a short anterior peduncle which is subtended by a 
translucent strip-like anteroventral process which is trunctated anteriorly. Petiole node subconical in 
profile, narrowly but bluntly rounded above, its anterior face more or less flat and its posterior face very 
slightly convex. Postpetiole node smaller, lower and narrower than petiole, but somewhat more broadly 
rounded above. All dorsal surfaces of head and body with standing hairs, the promesonotum with 6-7 pairs 
and the propodeum with 3 pairs, the anteriormost of which is very short. Sculpture absent except for 
hair-pits and metanotal cross-ribs. Colour glossy light brown. 

Holotype worker, South Africa: Port Elizabeth (ex. coll. G. Mayr) (BMNH). 

This conspicuous small species is founded on a single specimen from that part of the Mayr collection 
which has been deposited in BMNH. It bears a label in Mayr's writing which says 'minutum var. s. nahe 
madecass.' M. kelapre is not closely related to minutum (=monomorium) nor madecassum; its closest 
relative appears to be boerorum, also from South Africa. The two are separated by density of pilosity 
{boerorum having only 3-4 pairs of promesonotal hairs) and by the relatively very large propodeal spiracle 
of kelapre. 

Monomorium kineti Weber stat. n. 
(Fig. 64) 

Monomorium (Monomorium) minutum subsp. kineti Weber, 1943: 359, pi. 15, figs 10, 19. Syntype 
workers, female, male, Sudan: Imatong Mts, Mt Kineti, 10,458 ft (3190 m), 27.vii.1939, no. 1334 (MCZ 
syntype workers no. 1335) (N. A. Weber) (MCZ) [examined]. 

Worker. TL 2-2-2-4, HL 0-56-0-60, HW 0-45-0-48, CI 77-80, SL 0-46-0-47, SI 100-102, PW 0-26-0-30, 
AL 0-62-0-64 (6 measured). 

Clypeal carinae moderately developed, close together and not strongly divergent anteriorly. Anterior 
clypeal margin between apices of clypeal carinae approximately transverse to feebly concave, the carinal 
apices not marked by projecting denticles or sharply prominent angles. Maximum diameter of eye 
0.21-0.22 x HW and with 6-7 ommatidia in the longest row. In full-face view the eyes with their posterior 
margins at the midlength of the sides and the scapes, when laid straight back from their insertions, reaching 
the occipital margin. Head in full-face view with sides approximately straight to very shallowly convex, 
posteriorly the sides broadly curved to their junction with the short, centrally feebly concave, occipital 
margin. Head in profile with both dorsal and ventral surfaces convex. Promesonotum in profile with its 
dorsal outline evenly convex, the highest point just in front of the midlength and conspicuously on a much 
higher level than the propodeum. Posterior quarter of mesonotum abruptly truncated behind the final pair 
of hairs and descending about vertically to the conspicuously impressed broad metanotal groove. 
Propodeal dorsal outline gently sloping posteriorly then abruptly rounding into the steep declivity. 
Dorsum of propodeum flat or more usually weakly transversely concave between a pair of blunt and poorly 
defined longitudinal rims which separate the dorsum proper from the sides and which are divergent 
posteriorly. Propodeal spiracle large and conspicuous, not pinhole-like. Subpetiolar process very small 
indeed, vestigial in some individuals. Node of petiole in profile subconical and narrowly rounded above, 
the postpetiole smaller than the petiole, lower and evenly convex dorsally. Head and body unsculptured 
and smooth everywhere except for hair-pits and vestiges of sculpture on the pleurae. Metanotal groove 
traversed by long strong cross-ribs, which continue for some distance down the sides of the alitrunk. All 
dorsal surfaces of head and body with standing hairs present, the promesonotum with 6-7 pairs. Colour 
uniform dull yellow to brownish yellow. 

M. kineti is a distinctive species of the Afrotropical sc/ju/fzez'-complex and not closely related to 
minutum, as it was first described by Weber. M. kineti and its close relatives crawleyi, arboreum, firmum 
and vecte share, within the complex, the characters of broad metanotal groove which has long strong 



SOLENOPSIS GENUS-GROUP 397 

cross-ribs, and an enlarged very conspicuous propodeal spiracle. Weber (1943: 312-313) summarizes what 
little is known of the biology of this species . He notes that kineti is found on the tops of the highest peaks in 
the Imatong Mountains and occurs only at considerable elevations. The first nest found was in cavities in 
the base of a dead woody stem and in chambers in the surrounding soil. Other nests discovered were 
located in the soil under small stones, among the roots of grasses and in the pith-cavities of herbaceous 
stems. In the open the ants move sluggishly and may ascend tree trunks, but in general kineti appears to be 
subterranean. Coccids are tended in the underground galleries. 

Material examined 
Sudan: Imatong Mts (N. A. Weber). 

Monomorium lene Santschi 

Monomorium lene Santschi, 1920i>: 11, figs 2g-2h. Syntype workers, Zimbabwe: Salisbury (= Harare), 
iv.1917, no. 421 (R. W. Tucker) (BMNH; NMB) [examined]. 

Worker. TL 1-8-2-1, HL 0-45-0-51, HW 0-35-0-42, CI 78-84, SL 0-29-0-34, SI 79-85, PW 0-23-0-27, 
AL 0-48-0-53 (10 measured). 

Clypeal carinae close together posteriorly and widely divergent anteriorly, meeting the anterior margin 
in a pair of projecting angles or broad low denticles. Anterior margin of prominent median portion of 
clypeus distinctly concave between these angles, the concavity accentuating their projection. Maximum 
diameter of eye 0-21-0-23 x HW and with 5-6 ommatidia in the longest row. In full-face view the eyes 
situated in front of the midlength of the sides. Antennal scapes, when laid straight back from their 
insertions, failing to reach the occipital margin. Promesonotal dorsum shallowly convex in profile, sloping 
posteriorly to the narrow and only shallowly impressed metanotal groove. Metanotal cross-ribs present but 
short and inconspicuous. Propodeal spiracle large and dominating the sides of the sclerite. Node of petiole 
in profile low and subconical, narrowly rounded above. Anteroventral process of petiole peduncle an 
inconspicuous ridge which is truncated anteriorly and may be reduced in some individuals. Postpetiole in 
profile smaller and somewhat lower than the petiole, slightly anteroposteriorly compressed and broadly 
rounded above. All dorsal surfaces of head and body with numerous standing hairs, the promesonotum 
with 6-7 pairs. Head and body entirely lacking sculpture except for scattered minute hair-pits and 
metanotal cross-ribs. Colour yellow. 

In the leopoldinum-complex three species, borlei, lene, and leopoldinum, have relatively very large 
propodeal spiracles which dominate the side of the sclerite. This feature is best developed in leopoldinum 
itself (Fig. 66), but the spiracle is only fractionally smaller in lene. Of the three borlei has only 3 pairs of 
standing hairs on the promesonotal dorsum, whereas the other two have more than 4 pairs (usually 6-7) . M 
borlei also has relatively long antennal scapes (SI 90-93) compared to the other two, which together show a 
range of SI 79-86. Separation of leopoldinum and lene rests on colour (the former is brown, the latter 
yellow) and the fact that the propodeal spiracle tends to be even larger in the former than in the latter. 

Material examined 

Tanzania: no loc. (O. W. Richards). Zimbabwe: Harare (R. W. Tucker). Botswana: Shorobe (A. 
Russell-Smith); Kobies (Vernay-Lang). 

Monomorium leopoldinum Forel stat. n. 
(Fig. 66) 

Monomorium minutum var. leopoldinum Forel, 1905: 179. Syntype workers, Zaire: St Gabriel, and 

Stanleyville (Luja) (MNH) [examined]. 
Monomorium explorator Santschi, 19206: 12, figs la-b. Holotype worker, Gabon: Samkita (F. Faure) 

(NMB) [examined]. Syn. n. 
Monomorium aequum Santschi, 1928: 195, fig. 3b. Holotype worker, Zaire: Stanleyville (Reichensperger) 

(NMB) [examined]. Syn. n. 
Monomorium (Monomorium) estherae Weber, 1943: 361, pi. 15, fig. 18. Syntype workers, Sudan: 

Imatong Mts, 5050 ft (1540 m), 4.viii.l939, no. 1423 (N. A. Weber) (MCZ) [examined]. Syn. n. 

Worker. TL 1-9-2-4, HL 0-50-0-57, HW 0-38-0-46, CI 76-82, SL 0-32-0-39, SI 83-86, PW 0-24-0-30, 
AL 0-50-0-58 (20 measured). 



398 B. BOLTON 

Clypeal carinae moderately to sharply developed, widely divergent anteriorly and terminating on the 
anterior clypeal margin in a pair of broad low triangular teeth or prominences which are usually obtuse. 
Median portion of anterior clypeal margin, between this pair of prominences, conspicuously broadly 
evenly concave; the prominences marking a clear distinction between the anterior and lateral margins of 
the projecting median portion of the clypeus. Maximum diameter of eye 0-19-0-23 x HW and with 5-6 
ommatidia in the longest row. With the head in full-face view the eyes conspicuously in front of the 
midlength of the side, and the antennal scapes, when laid straight back, obviously failing to reach the 
occipital margin. In full-face view the sides of the head subparallel, the occipital margin broad and 
transverse or at most shallowly concave. Promesonotum evenly convex in profile and sloping evenly to the 
narrow moderately impressed metanotal groove. Propodeal outline highest at the metanotal groove and 
sloping posteriorly , the angle of the slope about the same as that of the mesonotum ; dorsum and declivity of 
propodeum meeting in a broadly rounded angle. Propodeal spiracle very large, dominating the side of the 
sclerite. Nodes of petiole and postpetiole somewhat anteroposteriorly compressed, conspicuously trans- 
verse in dorsal view. In profile the petiole node narrowly rounded above, usually with the anterior face 
extremely feebly concave and the posterior face extremely feebly convex. Postpetiole with its anterior face 
high, vertical or nearly so; dorsum rounded, more broadly so than the petiole node. Mesopleuron with 
faint to vestigial traces of sculpture and metanotal groove with short cross-ribs, otherwise the entire body 
unsculptured and smooth except for hair-pits. Standing pilosity dense on all dorsal surfaces of head and 
body, the promesonotum very obviously with more than 4 pairs of hairs and the propodeum with more than 
2 pairs. Colour light to dark brown, the legs the same colour as the alitrunk or slightly lighter. Rarely the 
legs much lighter than the alitrunk. 

There is some variation in this species over its wide range which may indicate that the name as presently 
applied contains 2 or more sibling species . For example , the Sudanese sample is lighter in colour than those 
from Zaire and Kenya, and tends to have the metanotal groove somewhat narrower. The sample from 
Kajiado, Kenya, has very pale legs, paler than in other Kenyan material, and has the petiole node more 
nearly conical. The composition of leopoldinum will require further attention when more material is 
available, but my present opinion is that the names explorator and aequum will remain as absolute 
synonyms. 

In Sudan Weber (1943) found this species nesting in the soil, the nest entrance forming a tiny crater. 

The closest relatives of leopoldinum are lene and the Angolan borlei. The latter species has longer scapes 
and is much less densely hairy, having only 3 pairs of standing hairs on the promesonotum and a single pair 
on the propodeum. M. lene is yellow in colour and has a somewhat smaller propodeal spiracle, but 
otherwise is very close to leopoldinum. 

Material examined 

Gabon: Samkita (F. Faure). Zaire: St Gabriel (Luja); Stanleyville (Luja); Stanleyville (Reichensperger). 
Sudan: Imatong Mts (N. A. Weber). Kenya: Narok, Loita Hills, Morijo (V. Mahnert & J.-L. Perret); 
Kajiado (W. Sands); Kiambu (R. H. le Pelley). 

Monomorium lubricum Arnold 

(Fig. 90) 

Monomorium lubricum Arnold, 1948: 217, fig. 7. Syntype workers, South Africa: Transvaal, Marieskop, 
vii.1944 (/. C. Faure) (SAM) [examined]. 

Worker. TL 2-3-2-5, HL 0-52-0-56, HW 0-44-0-47, CI 82-84, SL 0-35-0-38, SI 78-81, PW 0-27-0-28, 
AL 0-60-0-64 (5 measured). 

Prominent median portion of clypeus with its anterior margin approximately transverse to very feebly 
concave, usually with an exceptionally small central indentation. Clypeal carinae weakly developed, 
widely separated and strongly divergent anteriorly. Projecting median section of anterior clypeal margin 
rounding into the anterolateral sections, not angulate nor denticulate where the carinae run to the margin. 
Eyes of moderate size, their maximum diameter 0-20-0-22 x HW and with 5-6 ommatidia in the longest 
row. With the head in full-face view the posterior margins of the eyes in front of the midlength of the sides. 
Antennal scapes relatively short (SI < 85), when laid straight back on the head the scapes obviously failing 
to reach the occipital margin. In full-face view the sides of the head evenly shallowly convex and broadest at 
about the midlength. Occipital margin very shallowly transversely concave. Promesonotal dorsum evenly 
convex, sloping posteriorly to the weakly impressed narrow metanotal groove. Propodeal dorsum and 
declivity forming a single smooth even convexity in profile. Propodeal spiracle small. Petiolar peduncle 



SOLENOPSIS GENUS-GROUP 399 

short and stout, shorter than the height of the node. Subpetiolar process a large keel-like translucent 
lamella whose ventral margin is more or less straight. Dorsal surface of petiole node with a shallow median 
indentation. All dorsal surfaces of head and body with standing hairs present, the promesonotum with 6-7 
pairs. Entirety of body smooth and shining, unsculptured except for cross-ribs at the metanotal groove. 
Colour glossy dark brown. 

Known only from the short syntypic series, lubricum is distinguished from its relatives, paternun and 
nuptualis, by its very large and conspicuous subpetiolar process. 

Material examined 
South Africa: Transvaal, Marieskop (/. C. Faure). 

Monomorium mulatu nom. n. 

Tetramorium altinode Santschi, 1935a: 266, fig. 10. Holotype worker, Zaire: Matadi, x.1920 (L. Burgeon) 
(MRAC) [examined]. [Junior secondary homonym of M. altinode Santschi, 1910: 359.] 

Monomorium altinode (Santschi, 1935a) Bolton, 1980: 199. [Change of generic combination but without 
proposal of a replacement name.] 

Worker. TL 1-9-21, HL 0-42-0-52, HW 0-38-0-46, CI 88-92, SL 0-33-0-38, SI 80-85, PW 0-26-0-28, 
AL 0-50-0-54 (7 measured). 

Prominent median section of anterior clypeal margin broad and subrectangular, the anterior margin 
transverse to shallowly concave between a pair of low broad slightly projecting angles which separate the 
anterior and lateral margins of the prominent median section of the clypeus. Clypeal carinae weakly 
developed, widely separated and subparallel, only slightly divergent anteriorly. Maximum diameter of eye 
0-21-0-23 x HW and with 5-7 ommatidia in the longest row. With the head in full-face view the posterior 
margins of the eyes at the midlength of the sides and the scapes, when laid straight back , failing to reach the 
occipital margin. Head in full-face view short and broad (CI>85), the sides slightly convex and the 
occipital margin transverse or very nearly so. Alitrunk in profile with promesonotum evenly domed- 
convex, highest at about the midlength and sloping evenly posteriorly to the weakly impressed metanotal 
groove. Propodeal dorsum with a short more or less horizontal section behind the metanotal groove; this is 
followed by a long shallow convex curve which slopes posteriorly and is confluent with the declivity proper. 
Propodeal spiracle small and pinhole-like. Node of petiole high and narrow in profile, cuneate, very 
narrowly rounded above; subpetiolar process a conspicuous flange. Postpetiole node slightly smaller than 
that of petiole, somewhat anteroposteriorly compressed and with a vertical anterior face. Postpetiole 
dorsum conspicuously more broadly rounded than petiole. In dorsal view both nodes transverse, very 
obviously broader than long. All dorsal surfaces of head and body densely clothed with short standing 
hairs, most or all of which are blunt or truncated apically, the promesonotum with 8-10 pairs. Head 
unsculptured except for hair-pits, some weak sculpture immediately behind the frontal lobes and a narrow 
sculptured track on the side of the head which connects the eye to the mandibular insertion. Sides of 
alitrunk densely reticulate-punctate everywhere except for the pronotum (which is mostly smooth) and a 
small clear patch in front of the propodeal spiracle. Metanotal groove with fine narrow cross-ribbing. 
Pronotal dorsum smooth; mesonotal dorsum mostly smooth but usually with some faint sculpture on 
extreme lateral portions; propodeum reticulate-punctate. Petiole and postpetiole nodes reticulate to 
reticulate-punctulate laterally; their anterior, dorsal and upper-posterior surfaces usually smooth. Gaster 
unsculptured except for hair-pits. Colour dark brown to blackish brown. 

M. malatu is a very distinctive species, closest related to the much smaller affabile, the two being 
separated by both absolute and relative dimensions. These two share their characteristic cuneate petiole 
and high postpetiole with dolatu, but here the antennae have only 11 segments. More distantly all appear 
related to disoriente and tanysum; see the notes under the latter name. 

Material examined 

Zaire: Niangara (N. A. Weber) ; Matadi (L. Burgeon). Uganda: W. Buganda, Kayadondo, Kawand Res. 
Sta. (D. N. McNutt); Sabawali, Kigogwa (D. N. McNutt); Ankole, Igara, Bushenyi (D. N. McNutt). 
Central African Republic: Ubangi-shari, Haunt Mbomu (N. A. Weber). 



400 B. BOLTON 

Monomorium manir sp. n. 

Holotype worker. TL 1-8, HL 048, HW 0-36, CI 75, SL 0-32, SI 89, PW 0-23, AL 0-48. 

Clypeal carinae sharply defined and distinctly divergent anteriorly. Prominent median portion of clypeus 
with a pair of projecting low triangular denticles separating its anterior and lateral margins; the anterior 
margin shallowly concave between the denticles. Eyes relatively large and very conspicuous, their 
maximum diameter 0-31 x HW and with 7 ommatidia in the longest row. In profile the maximum diameter 
of the eye much greater than the shortest distance between the anteriormost point of the eye and the 
mandibular articulation. In full-face view the eyes distinctly in front of the midlength of the sides and the 
antennal scapes, when laid straight back from their insertions, failing to reach the occipital margin. Sides of 
head very feebly convex in full-face view and the broad occipital margin slightly concave. Promesonotal 
dorsum only shallowly convex in profile, sloping posteriorly to the impressed but narrow metanotal 
groove. Metanotal cross-ribs short but conspicuous. Propodeal spiracle very small, pinhole-like. Petiole in 
profile with a short stout anterior peduncle and with an anteroventral process which consists of a small low 
lobe which tapers posteriorly, not reaching back to the level of the spiracle. Node of petiole narrow and 
subconical, higher than the postpetiole and noticeably more narrowly rounded above. Dorsal surfaces of 
head and body moderately clothed with standing hairs, the promesonotum with 4-5 pairs of which the 
longest are those at the pronotal humeri. Sculpture absent except for scattered minute hair-pits, metanotal 
short cross-ribs and some faint vestiges at about the mid-height of the mesopleuron. Colour shiny dark 
brown, the appendages and ventral surface of the head lighter. 

Holotype worker, Kenya: Kora, Tana Riv., 1983, 0-100 m, no. 21, Acacia-Commiphila scrub (N. M. 
Collins & M. Ritchie) (BMNH). 

Known from the holotype only, this small darkly coloured large-eyed species is related to balathir, 
holothir and katir. For separation of the four see the notes under balathir. 

Monomorium mavide sp. n. 

Holotype worker. TL 1-4, HL 0-38, HW 0-31 , CI 82, SL 0-24, SI 77, PW 0-20, AL 0-38. 

Clypeal carinae present and running to anterior margin. Maximum separation of carinae about equal to 
diameter of antennal socket, the carinae only very feebly divergent anteriorly. Anterior and lateral 
margins of prominent median portion of clypeus meeting in a blunt and obtuse angle, the margin without 
projecting angles or denticles at their junction. Anterior clypeal margin between apices of clypeal carinae 
transverse. Maximum diameter of eye 0T9 x HW and with 5 ommatidia in the longest row. In full-face 
view the eyes far in front of the midlength of the sides of the head. Antennal scapes relatively very short 
(SI < 80), when laid straight back from their insertions conspicuously failing to reach the occipital margin. 
Sides of head feebly convex in full-face view, head broadest behind the level of the eyes then narrowing 
somewhat to the occipital margin, which is extremely shallowly concave; head broader across the occiput 
than the clypeus. Head in profile with dorsal surface flat and ventral surface weakly convex. Anterior half 
of pronotum in profile convex but posterior half of pronotum and all of mesonotum flat, scarcely sloping 
towards the metanotal groove. Metanotal groove narrow and only shallowly impressed, the propodeal 
dorsum behind the groove more or less continuing the line of the promesonotum, then rounding broadly 
into the declivity. Propodeal spiracle very small, the metanotal cross-ribs short and only weakly developed. 
Petiole with a short stout anterior peduncle which is subtended by a narrow strip-like anteroventral 
process, the process truncated anteriorly. Node of petiole bluntly sub-conical, its ventral border convex 
and bulging. Postpetiole smaller, lower and more broadly rounded than petiole, its dorsum evenly 
domed-convex. All dorsal surfaces of head and body with standing hairs present, the promesonotum with 
4-5 pairs. Sculpture absent except for minute hair-pits and metanotal cross-ribs. Head and gaster brown, 
the alitrunk light brownish yellow. 

Paratype workers. TL 1-4-1-5, HL 0-38-0-40, HW 0-30-0-32, CI 79-82, SL 0-24-0-25, SI 75-80, PW 
0-20-0-21, AL 0-38-0-40, (5 measured). As holotype but generally with alitrunk the same colour as the 
head. 

Holotype worker, South Africa: Natal, Drakensberg, Giant's Castle, 2200 m, 1981 (C. Peelers) 
(BMNH). 
Paratypes. 5 workers with same data as holotype (BMNH; MCZ). 



SOLENOPSIS GENUS-GROUP 401 

M. mavide and torvicte, also from South Africa, form a very close pair of minute and apparently 
uncommon species within the boerorum-comp\e\. The two are separated by the following characters. 

mavide torvicte 

Averaging smaller, HL 0-38-0-40, SL 0-24-0-25, Averaging larger, HL 0-44-0-45, SL 0-25-0-28, 

HW 0-30-0-32. HW 0-33-0-35. 

Eyes slightly smaller (019 x HW) and subcircular Eyes slightly larger (0-20-0-21 x HW) and 

in profile, only very little longer than wide. distinctly longer than wide in profile. 

Promesonotum flat behind anterior convexity, Promesonotum shallowly convex behind anterior 

scarcely sloping to metanotal groove. convexity, sloping to metanotal groove. 

Clypeal carinae weakly divergent anteriorly. Clypeal carinae conspicuously divergent 

anteriorly. 

Monomorium mid Ms Forel stat. n. 

Monomorium {Mania) atomus subsp. tnictilis Forel, 1910J: 252. Syntype workers, females, Ethiopia: 

Ghinda, Nefassit (K. Escherich) (MHN) [examined], 
Monomorium (Lampromyrmex) exiguum st. mictile var. sudanicum Santschi, 1930a: 67, figs 22-24. 

Syntype workers, Sudan: Koulouba (Claveau) (NMB) [examined]. [Unavailable name.] 
Monomorium minutissimum Santschi, 1937: 225, figs 27, 28. Holotype worker, Angola: Ebanga, 

1932-33, no. 134 (A. Monard) (NMB) [examined: holotype with head missing.] Syn. n. (provisional). 

Worker. TL 1-2-1-3, HL 0-36-0-40, HW 0-26-0-30, CI 72-76, SL 0-20-0-26, SI 77-86. PW 016-0-19, 
AL 0-32-0-36 (10 measured). 

Median portion of clypeus distinctly prominent and its anterior margin transverse to shallowly convex, 
sometimes with a minute indentation at the site of the median seta. Clypeal carinae weakly developed but 
present. Maximum diameter of eye 0-20-0-22 x HW. In general the eye when viewed in profile consisting 
of an outer ring of ommatidia encircling a single longitudinal row of only 2-3 ommatidia, but in some 
individuals one or two extra ommatidia may also be enclosed in the ring. Eye always distinctly longer than 
high and situated well in front of the midlength of the sides of the head. Antennae with 1 1 segments; the 
scape, when laid straight back from its insertion, conspicuously failing to reach the occipital margin. Head 
capsule in profile dorsoventrally flattened, the ventral surface approximately flat and not more convex than 
the dorsum. Promesonotal dorsum in profile flat or only extremely shallowly convex anteriorly, the 
metanotal groove only very weakly impressed. Propodeal dorsum convex and sloping posteriorly, the 
dorsum and declivity forming a single broadly convex surface. Propodeal spiracle small. Petiolar peduncle 
short and stout, subtended by a narrow strip-like and inconspicuous ventral process. Petiole node low and 
bluntly triangular in profile, distinctly larger than the much more broadly rounded postpetiole. Standing 
hairs present on all dorsal surfaces of the head and body, the promesonotal dorsum with only 3 pairs. 
Anterior margin of pronotum without a pair of elongate standing hairs between the distinctive pair at the 
pronotal humeri. Sculpture absent except for short metanotal cross-ribs. Colour dull yellow. 

As presently constituted this minute species is identified by its size, arrangement of alitrunk pilosity and 
flattened head, in combination with the 11-segmented antennae. Of the names given above Santschi's 
unavailable sudanicum specimens are certainly conspecific with the mictilis type-series but the identity of 
minutissimum remains in some doubt as the holotype is headless. 

M. mictilis has a wide distribution in the Afrotropical region. Material of the species is relatively scarce 
but I suspect that the individuals from Kenya, noted below, may eventually prove to be separate from the 
rest as they usually show one or two extra ommatidia in the eye. More collections are necessary to see if this 
variation occurs elsewhere in the range or is restricted to Kenyan populations, so for the present all the 
samples are retained as a single species. 

Material examined 

Ethiopia: Ghinda, Nefassit (K. Escherich). Sudan: Koulouba (Claveau). Kenya: Tana Riv. Distr., 
Gersen(V. Mahnert &J.-L. Perret) ; Galole, Hola (V. Mahnert &J.-L. Perret), Zimbabwe: Bulawayo(G. 
Arnold). Angola: Ebanga (A. Monard). Namibia: Ganab (R. Leggott). 

Monomorium mirandum Arnold 

Monomorium (Monomorium) mirandum Arnold, 1955: 734, fig. 2. Syntype workers, Kenya: Diani 
Beach, vii.1951 (N. L. H. Krauss) (MCZ) [examined]. 



402 B. BOLTON 

Worker. TL 1-8-1-9, HL 0-50-0-52, HW 0-38-0-39, CI 74-76, SL 0-38, SI 97-100 PW 0-26, AL 
0-50-0-54, (3 measured). 

Clypeal carinae conspicuous, widely separated and divergent anteriorly, terminating at the anterior 
clypeal margin in a pair of short but quite broad triangular denticles. Prominent median portion of clypeus 
with its margin transverse between the denticles, the latter distinctly separating the anterior and lateral 
margins. Maximum diameter of eye 0-21-0-23 x HW and with 6 ommatidia in the longest row. With the 
head in full-face view the posterior margins of the eyes distinctly in front of the midlength of the sides of the 
head. Antennal scapes, when laid straight back from their insertions, just failing to reach the occipital 
margin; the latter shallowly concave. Promesonotal dorsum evenly convex in profile, conspicuously higher 
than the propodeum. Metanotal groove broadly impressed but metanotal cross-ribs very short, scarcely 
longer than the width of the minute pinhole-like propodeal spiracle. Propodeal dorsum highest immedi- 
ately behind the metanotal groove, the surface then sloping posteriorly, feebly convex and rounding 
broadly and evenly into the declivity. Peduncle of petiole narrow, its ventral process reduced to an 
insignificant short ridge. Node of petiole high and narrow, triangular and tapering to a narrowly rounded 
point dorsally. Anterior and posterior faces of petiole node meeting in a sharp rim or edge, which is 
continuous around the sides and dorsum. Node of postpetiole very high and narrow, almost as high as 
petiole, tapering dorsally but more broadly rounded than the petiole node. Anterior face of postpetiole 
vertical, and laterally with the anterior and posterior faces meeting in a rim or edge, but this does not 
continue across the dorsum. All dorsal surfaces of head and body with standing hairs present, the 
promesonotum with 5-6 pairs. Sculpture absent except for scattered hair-pits and the short metanotal 
cross-ribs. Spectacularly bicoloured species. Head and its appendages, legs, and gaster bright yellow; 
alitrunk petiole and postpetiole blackish brown to black. 

The very distinctive colour pattern of mirandum renders it immediately identifiable among the 
Afrotropical Monomorium fauna. The species belongs to the altinode-complex and the structure of its 
petiole and postpetiole indicates that it is closest related to the Ghanaian vonatu. The latter is uniformly 
black in colour and has much shorter scapes (SI 83). 

Material examined 

Kenya: Diani Beach (N. L. H. Krauss) 

Monomorium musicum Forel 

Monomorium oscaris subsp. musicum Forel, 19106: 442. Syntype workers, female, South Africa: Natal 

no. 156 (Haviland) (MNH; BMNH) [examined]. 
Monomorium musicum Forel; Emery, 1922: 173. [Raised to species.] 

Worker. TL 1-6-1-7, HL 0-42-0-44, HW 0-32-0-33, CI 73-76, SL 0-26-0-27, SI 81-84, PW 0-20-0-22, 
AL 0-40-0-42 (3 measured). 

Clypeal carinae narrow but sharply defined posteriorly, divergent anteriorly and tending to fade out 
before reaching the anterior margin. Prominent median portion of clypeus transverse on its anterior 
margin and with an obtuse angle separating the anterior and lateral margins, but without projecting teeth 
or denticles. Maximum diameter of eye 0-22-0-24 x HW and with 6 ommatidia in the longest row. With 
the head in full-face view the eyes very obviously far in front of the midlength of the sides. Antennal scapes, 
when laid straight back from their insertions, falling far short of the occipital margin. Sides of head 
shallowly convex and divergent posteriorly, so that the width of the head at the occipital margin is greater 
than its width immediately in front of the eyes. Occipital margin broad and weakly concave medially. 
Promesonotum in profile low, scarcely higher than the highest point of the propodeum. Dorsum of 
promesonotum more or less flat in profile, downcurved anteriorly to the cervix and posteriorly to the 
narrow and weakly impressed metanotal groove; the latter with few short inconspicuous cross-ribs. 
Propodeal dorsum highest immediately behind the metanotal groove, the dorsum then rounding evenly 
into the declivity through a broad smooth curve. Propodeal spiracle small. Petiole node low subconical in 
profile, with a short anterior peduncle which is subtended by a small subtriangular and flange-like 
anteroventral process. Postpetiole much smaller than petiole, its dorsum low and evenly convex. All dorsal 
surfaces of head and body with standing hairs, 3-4 pairs present on the promesonotum. Sculpture absent 
except for minute hair-pits and metanotal cross-ribs. Colour yellow, the head and gaster of some 
individuals with a faint brownish tint. 



SOLENOPSIS GENUS-GROUP 403 

This minute species is superficially similar to braunsi, but in the latter the petiole node is very low and 
broadly convex dorsally, and the anterior peduncle of the node lacks a prominent anteroventral process. 
M. torvicte, a close relative of musicum, is uniformly dark brown and has shorter scapes and smaller eyes 
but is otherwise very similar indeed. I have treated these as separate species for the present but suspect that 
further collecting may nullify the apparent differences between them. 

Material examined 

South Africa: Natal (Haviland). 

Monomorium noxitum sp. n. 

Holotype worker. TL 2- 1, HL 0-49, HW 0-40, CI 82, SL 0-42, SI 105, PW 0-27, AL 0-56. 

Answering the description of draxocum holotype and with biconvex head as shown for gabrielense (Fig. 
76). Differing from draxocum holotype by having 7 ommatidia in the longest facet-row of the eye. The 
metanotal cross-ribs are much more distinct laterally than in draxocum and are not confused with the 
strong reticulate-punctate sculpture of the mesopleuron. Head and alitrunk brown, with blackish brown 
gaster; legs scarcely lighter in shade than alitrunk. 

Paratype workers. TL 2-0-2-1, HL 0-46-0-50, HW 0-37-0-40, CI 79-82, SL 0-39-0-42, SI 103-105, PW 
0-24-0-27, AL 0-54-0-58 (8 measured). As holotype but maximum diameter of eye 0-22-0-26 x HW 
(0-23 x HW in holotype) and with 6-7 ommatidia in the longest row. 

Holotype worker, Cameroun: Nkoemvon, 1980 (D. Jackson) (BMNH) 
Paratypes, 8 workers with same data as holotype (BMNH; MCZ; MHN) 
Non-paratypic material examined. Cameroun: Mt Cameroun, Jonga (M. Steele). 

Very closely related to draxocum, the two are separated as follows: 

draxocum noxitum 

HL 0-39-0-42, HW 0-32-0-35. HL 0-46-0-50, HW 0-37-0-40. 

SL 0-32-0-36 (SI 100-109). SL 0-39-0-42 (SI 103-105). 

AL 0-44-0-46. AL 0-54-0-58. 

Maximum diameter of eye 0-21-0-24 x HW, with Maximum diameter of eye 0-22-0-26 x HW, with 

5-6 ommatidia in longest row. 6-7 ommatidia in longest row. 

Legs very pale, conspicuously much lighter than Legs only slightly lighter in colour than alitrunk. 

alitrunk. 

Propodeal spiracle of moderate size. Propodeal spiracle large. 

Alitrunk very dark brown. Alitrunk light brown. 

Monomorium nuptualis Forel stat. n. 

Monomorium oscaris var. nuptualis Forel, 1913c: 216. Syntype workers, Zimbabwe: Bembesi, no. 146 (G. 
Arnold) (MHN) [examined]. 

Worker. TL 1-8, HL 0-46, HW 0-36, CI 78, SL 0-32, SI 89, PW 0-24, AL 0-46 (one of two syntypes 
measured, head of second syntype crushed). 

Clypeal carinae conspicuous, widely divergent anteriorly and running to the anterior margin. Prominent 
median portion of clypeus narrowly indented at site of median seta; the anterior margin of the prominent 
portion rounding into the lateral margins, the two not separated by sharp angles or projecting denticles. 
Maximum diameter of eye 0-22 x HW, with 5 ommatidia in the longest row. In full-face view the eyes far in 
front of the midlength of the sides and the scapes, when laid straight back from their insertions, failing to 
reach the occipital margin. Head subrectangular in full-face view, slightly narrower behind than in front 
and with a broad, medially concave occipital margin. With the alitrunk in profile the promesonotum 
forming a low shallow curve, the mesonotum sloping evenly and gradually backwards to the metanotal 
groove, not suddenly descending to meet it. Metanotal groove scarcely impressed, forming only the 
shallowest of indentations in the surface; metanotal cross-ribs very short and feeble. Propodeal dorsum 
shallowly convex, highest just behind the metanotal groove, then evenly downcurved posteriorly. 
Propodeal spiracle minute and pinhole-like. Petiole node thickly and bluntly subconical, the posterior face 
somewhat more convex than the anterior. Subpetiolar process a conspicuous anteroventral strip. Post- 



404 B. BOLTON 

petiole smaller, lower and more bluntly rounded than petiole in profile; in dorsal view both nodes 
appearing thickly subglobular. All dorsal surfaces of head and body with standing hairs, the syntypes 
somewhat abraded but the promesonotum probably with 4-5 pairs of hairs in life. Sculpture absent apart 
from minute hair-pits and the feeble metanotal cross-ribs. Colour glossy light brown to yellowish brown. 

This species resembles a small, lighter coloured and relatively larger-eyes version of paternum, to which 
it is closely related. 

Material examined 

Zimbabwe: Bembesi (G. Arnold). 

Monomorium occidentale Bernard 

(Fig. 73) 

Monomorium occidentale Bernard, 1952: 326, figs 10A-10E. Lectotype worker, Guinea: Ziela Savano- 
To, 850 m (Lamotte) (MNHN) (here designated) [examined]. 

Worker: TL 1-8-2-1, HL 0-48-0-54, HW 0-38-0-44, CI 76-81, SL 0-32-0-36, SI 80-87, PW 0-26-0-30, 
AL 0-50-0-60 (10 measured). 

Clypeal carinae distinct, divergent anteriorly and the space between the carinae transversely shallowly 
concave. Anterior clypeal margin characteristically shaped and isolating the species from all other 
Afrotropical members of the group, being equipped with a pair of elongate narrow anteriorly projecting 
teeth at the corners of the prominent median portion of the clypeus. The teeth are usually slightly curved 
towards the midline and the anterior clypeal margin between them is conspicuously concave. Maximum 
diameter of eye 0-20-0-23 x HW and with 5-7 ommatidia in the longest row. In full-face view the eyes in 
front of the midlength of the sides. Antennal scapes, when laid straight back from their insertions, failing to 
reach the occipital margin; the latter broad and shallowly concave. Promesonotum evenly shallowly 
convex in profile, sloping posteriorly to the narrow but distinctly indented metanotal groove. Metanotal 
cross-ribs short but conspicuous. Propodeal spiracle very large, dominating the side of the sclerite. Petiole 
in profile with a high narrow node and a small lobate anteroventral process on the short peduncle. 
Postpetiole with a vertical anterior face, not as high as the petiole and more broadly rounded above. All 
surfaces of head and body with numerous standing hairs, the promesonotum with 7 or more pairs and the 
propodeum usually with 5 pairs. Sculpture absent except for scattered minute hair-pits and metanotal 
cross-ribs. Some specimens with sculptured vestiges on the mesopleuron. Colour dark brown, the gaster 
tending to blackish brown in some. 

The form of the clypeus in occidentale is reminiscent of the Madeiran carbonarium, but in the latter 
species the metanotal groove is broad and strongly cross-ribbed, the clypeal teeth are by no means as 
spectacularly developed, and the petiolar peduncle is relatively longer. The overall appearance of 
occidentale is that of a very specialized member of the altinode-comp\ex, immediately isolated by the form 
of the clypeus and its teeth. 

The above lectotype designation was rendered necessary by Bernard's inclusion of some workers 
referable to invidium in the type-series of occidentale . Those referable to invidium were Bernard's 
'cotypes' from NE. Nimba ( Villiers). Bernard's 'types' bearing the numbers F108, T125, T127, T128, T130, 
and the female T125 are now designated paralectotypes of occidentale . 

Material examined 
Sierra Leone: Njala (F. A. Squire); Njala (E. Hargreaves). Guinea: Ziela (Lamotte). 

Monomorium pads Forel nomen dubium 

Monomorium pads Forel, 1915: 343. Holotype worker. South Africa: Cape Town (not in MHN or SAM, 
presumed lost). 

Forel's description of this enigmatic species is too vague to allow even a guess at its correct placement. 
He says that pads has something of the appearance of Bondroita, but other characters which he mentions 
indicate that the species is correctly placed in Monomorium. 

Features which Forel stresses , which may be of value in recognizing this species , if it is ever rediscovered , 
include the following. 



SOLENOPSIS GENUS-GROUP 405 

TL 1-9, smaller than leimbachi (a junior synonym of rhopalocerum) . Profile of head subtruncate in front 
of the clypeus. Frontal carinae posteriorly forming a strong curve with their anterior lobe , which is situated 
on the subtruncate region. Eyes with about 15-20 ommatidia, situated on the anterior third of the sides of 
the head. 

Monotnorium pallidipes Forel stat. n. 

Monomorium minutum var. pallidipes Forel, 1910c: 252. Syntype workers, Ethiopia: Nefassit (K. 
Escherich) (MHN) [examined]. 

Worker. TL 1-5, HL 0-41-0-42, HW 0-33-0-34, CI 79-81, SL 0-28-0-29, SI 83-88, PW 0-20-0-21, AL 

0-39-0-40 (3 measured). 

Clypeal carinae moderately well developed, clearly visible, reaching the anterior margin and strongly 
divergent anteriorly ; the anterior margin and the carinae forming almost an equilateral triangle. Prominent 
median portion of clypeus broad and sharply defined, with a transverse to slightly concave anterior margin 
between the apices of the clypeal carinae and with an obtuse but conspicuous angle between the anterior 
and lateral margins. The clypeal carinae meet the anterior margin mesad of the angles separating anterior 
and lateral margins. Maximum diameter of eye 0-18-0-20 x HW, with 5 ommatidia in the longest row. 
With the head in full-face view the eyes distinctly in front of the midlength of the sides and the scapes, when 
laid straight back from their insertions, failing to reach the occipital margin. Sides of head straight to 
shallowly convex in full-face view, the occipital margin broad and shallowly concave. Head in profile 
dorsoventrally flattened, the dorsal and ventral surfaces only feebly convex. Promesonotum in profile low 
and shallowly convex, scarcely higher than the propodeum. Metanotal groove broadly but shallowly 
impressed, traversed by short but sharply defined cross-ribs. Propodeum highest immediately behind the 
metanotal groove where it is only slightly lower than the highest point of the promesonotum. Behind this 
the dorsum very shallowly convex and sloping posteriorly, then rounding broadly and evenly into the short 
declivity. Propodeal spiracle small and relatively high on the side. Petiole with a short stout anterior 
peduncle and a low broadly subconical node. Subpetiolar process an elongate narrow strip which runs back 
to a point just posterior to the level of the spiracle. Postpetiole smaller and lower than the petiole, more 
broadly rounded above. All dorsal surfaces with standing hairs, the promesonotum with 5 pairs. Sculpture 
absent except from the metanotal cross-ribs and minute scattered hair-pits. Colour uniform medium to 
dark brown. 

This small dark Ethiopian species is known only from the type-series. Although related to monomorium 
(=minutum) it is distinctly different in the construction of the clypeus, shape of the alitrunk and form of the 
petiole and its ventral process. In monomorium the prominent median portion of the anterior clypeus is 
narrow and distinctly notched or indented, the propodeum is shorter and more strongly convex, and the 
subpetiolar process is a small lobe. The real affinities of pallidipes lie with leopoldinum , and its Afrotropical 
allies. 

Material examined 
Ethiopia: Neffasit (K. Escherich). 

Monomorium paternum sp. n. 

(Fig. 89) 

Monomorium oscaris r. springvalense var. paterna Forel, 1914: 248. Holotype worker, South Africa: 
Cape Prov., Table Mt, no. 300 (G. Arnold) (MHN) (examined). [Unavailable name.] 

Holotype worker. TL 2-3, HL 0-53, HW 0-44, CI 83, SL 0-36, SI 82, PW 0-28, AL 0-56. 

Clypeal carinae moderately developed, widely separated posteriorly, outcurved, strongly divergent and 
petering out anteriorly. Prominent median portion of clypeus broad, its anterior margin concave in the 
middle of its width, the concavity not extending to the anterolateral angles of the prominent median 
portion of clypeus. Anterior and lateral margins of prominent median portion of clypeus separated by a 
broad blunt angle, without projecting angles or denticles of any description. Maximum diameter of eye 
0-18 x HW and apparently with 5-6 ommatidia in the longest row. The actual number is difficult to discern 
as both eyes of the holotype are concave centrally. Whether this feature occurs in live individuals or is an 
artifact of preservation is not known . With the head in full-face view the eyes well in front of the midlength 
of the sides and the scapes, when laid straight back, failing to reach the occipital margin. Sides of head 



406 B. BOLTON 

behind eyes shallowly convex and feebly convergent posteriorly, rounding into the broad and shallowly 
concave occipital margin. Head dorsoventrally flattened, in profile only weakly biconvex. Promesonotum 
only feebly convex, sloping posteriorly to the narrow and shallowly impressed metanotal groove. 
Propodeum feebly convex, sloping posteriorly and the dorsum rounding broadly and evenly into the 
declivity. Propodeal spiracle small. Petiole with a short stout anterior peduncle which is equipped below 
with a broad translucent strip-like process. Postpetiole node smaller than petiole in profile, in dorsal view 
both nodes broader than long. Holotype abraded but all dorsal surfaces apparently with standing hairs 
present, the promesonotum probably with 4-5 pairs in life. Entire body smooth and shining, lacking 
sculpture except for minute hair-pits and metanotal cross-ribs. Colour glossy medium to dark brown. 

Holotype worker, South Africa: Cape Prov., Table Mt, no. 300 (G. Arnold) (MHN). 

Known only from the holotype, this medium-sized species appears closest related to lubricum and 
nuptualis. The former is distinguished by its much more massively developed subpetiolar process. The 
latter is a smaller species with a relatively longer head, longer scapes and smaller eyes. 

Monomorium pulchrum Santschi 

Monomorium (Lampromyrmex) pulchrum Santschi, 1926a: 238, fig. 3A. Syntype workers, Zimbabwe: 
Sawmills, 27.xii.1923 (G. Arnold) (BMNH; MCZ) [examined]. 

Worker. TL 1-7-1-9, HL 0-44-0-48, HW 0-36-0-38, CI 78-82, SL 0-32-0-34, SI 87-92, PW 0-22-0-26, 
AL 0-50-0-54 (8 measured). 

Clypeal carinae finely but sharply developed, widely separated and strongly divergent anteriorly. 
Anterior clypeal margin transverse to feebly convex between the apices of the carinae. Anterior and lateral 
faces of the projecting median portion of the clypeus separated by an obtuse angle, without projecting 
teeth. Fourth (basal) tooth of mandible much smaller than the third, reduced to a denticle. Maximum 
diameter of eye 0-18-0-21 x HW and with 5-6 ommatidia in the longest row. Outer ring of ommatidia 
enclosing more than one transverse row. In full-face view the eyes conspicuously in front of the midlength 
of the sides. Antennae with 11 segments; the antennal scapes, when laid straight back from their insertions, 
failing to reach the occipital margin. In full-face view the occipital margin very feebly concave medially. 
Promesonotum evenly shallowly convex in profile, the metanotal groove broad, deeply impressed and 
traversed by sharply defined ribs. Propodeal dorsum convex, highest approximately above the level of the 
small pinhole-like spiracle. Posteriorly the dorsum rounding broadly into the declivity. Petiole node high 
and quite narrowly subconical in profile, narrowly rounded above. Subpetiolar process a narrow longitu- 
dinal strip, the ventral margin of the petiole node shallowly convex behind the process but not strongly 
bulging downwards. Postpetiole in profile approximately as voluminous as the petiole, almost as high but 
distinctly more broadly rounded above. Anterior face of postpetiole shallowly convex, the posterior face 
much longer than the anterior and more or less flat in profile, sloping at about 45°. In dorsal view both 
nodes distinctly broader than long, the postpetiole broader than the petiole. All dorsal surfaces of head and 
body with conspicuous fine standing hairs, the promesonotum with 6-7 pairs and the propodeum with 2-3 
pairs. Sculpture absent except for metanotal cross-ribs and some faint shagreening on the pleurae. Colour 
of head and alitrunk glossy dull yellow to pale brown, the gaster somewhat darker brown. 

M. pulchrum is closest related to the darker coloured bequaerti from Zaire. Of the species with 11 
antennal segments these two form a close complex with rosae, a common West and Central African form 
which is blackish brown to black in colour. M. pulchrum separates from bequaerti by colour and size, and 
by the fact that the nodes of both petiole and postpetiole are longer than broad in dorsal view in bequaerti, 
both broader than long in pulchrum. 

Material examined 

Zimbabwe: Sawmills (G. Arnold); Bulawayo (G. Arnold) 

Monomorium rastractum sp. n. 

Holotype worker. TL 1 -9, HL 0-50, HW 0-37, CI 74, SL 0-34, SI 92, PW 0-24, AL 0-50. 

Clypeal carinae widely separated, strongly divergent anteriorly, terminating at the anterior margin in a 
pair of low, relatively broad projecting angles. Prominent median portion of clypeus with its anterior 
margin extremely feebly concave between the projecting angles, the latter separating its anterior and 
lateral margins . Eyes relatively large , • 27 x HW and with 7 ommatidia in the longest row . In full-face view 



SOLENOPSIS GENUS-GROUP 407 

the large eyes conspicuously in front of the midlength of the sides. Antennal scapes, when laid straight back 
from their insertions, distinctly failing to reach the occipital margin. Sides of head shallowly convex behind 
the eyes and somewhat convergent posteriorly. Occipital margin shallowly concave medially. Prome- 
sonotal dorsum in profile shallowly convex, highest at about the midlength of the pronotum, the posterior 
half of the pronotum and the entire mesonotum forming a gradual slope to the metanotal groove; the latter 
only weakly and quite narrowly impressed. Metanotal cross-ribs short but conspicuous. Propodeal spiracle 
minute and pinhole-like. Propodeal dorsal outline forming a single even long convexity in profile, without 
obvious division into dorsum and declivity. Petiole node in profile small, low and subconical, with a low 
lobe-like anteroventral process which tapers out posteriorly. Postpetiole smaller than petiole, slightly 
more broadly rounded above. All dorsal surfaces of head and body with standing hairs, the promesonotum 
with 6-7 pairs. Sculpture absent except for scattered minute hair-pits and metanotal cross-ribs. Colour 
yellow. 

Holotype worker, Kenya: Tana Riv., Kora, 0-100 m, no. 5, 1983, Acacia-Commiphila scrub (TV. M. 
Collins & M. Ritchie) (BMNH). 

A very distinctive species with relatively large eyes, rastractum combines the clypeal structure of the 
altinode-complex with the petiole form of the leopoldinum-comp\ex and appears to represent an intermedi- 
ate between these two informal groups. The outline shape of the alitrunk in rastractum is very similar to 
that of fugelanum (Fig. 88), but the petiole is lower, much smaller and more obviously conical. The 
postpetiole lacks the high vertical anterior face shown by fugelanum and its allies in the altinode-complex. 
Within the leopoldinum-complex rastractum is closest related to borlei and springvalense, but the former 
has a large propodeal spiracle and only 3 pairs of standing hairs on the promesonotum. The latter also has 
only 3-4 pairs of standing hairs on the promesonotum, and has a broader head and relatively smaller eyes 
than rastractum, 0-21-0-23 x HW as opposed to 0-27 x HW. 

Monomorium rhopalocerum Emery 
(Fig. 81) 

Monomorium rhopalocerum Emery, 18956: 25, pi. 2, fig. 29. Syntype workers. South Africa: Cape Town 

(E. Simon) (MCSN) [examined]. 
Monomorium minutum subsp. hottentota Emery, 18956: 26. Syntype females (dealate), South Africa: 

Cape Town (E. Simon) (MCSN) [examined]. Syn. n. (provisional). 
Monomorium leimbachi Forel, 1914: 246. Syntype workers, South Africa: Cape Town, 1913, No. 336 

(G. Arnold) (MHN) [examined]. Syn. n. 

Worker. TL 2-0-2-2, HL 0-53-0-60, HW 0-42-0-50, CI 79-83, SL 0-36-0-44, SI 83-90, PW 0-26-0-30, 
AL 0-55-0-60 (15 measured). 

Anterior margin of prominent median portion of clypeus transverse to shallowly concave , rounding into 
the lateral margin; the two margins not separated by acute angles or projecting triangular denticles. 
Clypeal carinae narrow but sharply developed, the space between them extremely shallowly transversely 
concave. Clypeal carinae relatively close together posteriorly and subparallel, feebly diverging anteriorly. 
Eyes relatively small, their maximum diameter 0-18-0-21 x HW and with 6-7 ommatidia in the longest 
row. In full-face view the eyes conspicuously in front of the midlength of the sides of the head. Antennal 
scapes, when laid straight back from their insertions, failing to reach the occipital margin. Sides of head 
behind eyes approximately parallel, only extremely weakly convex and feebly convergent posteriorly. 
Occipital margin broad and usually very weakly and shallowly concave, at least medially. Promesonotal 
dorsum evenly broadly and shallowly convex in profile, sloping posteriorly to the broadly impressed 
metanotal groove. Metanotal cross-ribs relatively long and strong, conspicuous. Propodeal dorsum sloping 
posteriorly, rounding broadly and evenly into the declivity. Propodeal spiracle small. Subpetiolar process a 
narrow inconspicuous rim. Node of petiole in profile low and broad, broadly rounded above. Postpetiole 
much smaller than petiole, lower and its dorsal and anterior surfaces forming a single convexity. All dorsal 
surfaces of head and body with standing hairs, the promesonotum with 4-5 pairs. Mesopleuron shagreen- 
ate to finely reticulate in larger workers, partly smooth in small individuals. Sculpture otherwise absent 
except for scattered hair-pits and the conspicuous metanotal cross-ribs. Colour dull yellow, the gaster 
sometimes with a brownish tint. 

M. rhopalocerum is closely related to exchao, binatu and symmotu; and more distantly to tablense. Of 
these five binatu has relatively long scapes (SI 100-105) which reach back to the occipital margin. Both 



408 B. BOLTON 

binatu and tablense contrast with the remainder as their petiole nodes are relatively high and narrow (Figs 
78, 80) as opposed to the broader lower nodes seen in the other three (Figs 77, 79, 81). M. rhopalocerum is 
larger than exchao and symmotu, and has a relatively broader head, but relative size of eyes and length of 
scapes fall into the same range in all three, though the scapes of rhopalocerum average a fractionally lower 
SI. 





HW 


CI 


SL 


SI 


Diameter of eye 


rhopalocerum 


0-42-0-50 


79-83 


0-36-0-44 


83-90 


0-18-0-21 x HW 


symmotu 


0-36-0-39 


74-76 


0-34-0-35 


89-94 


0-20-0-23 x HW 


exchao 


0-37-0-38 


74-76 


0-34 


89-91 


0-20-0-21 x HW 



Apart from the dimensions symmotu differs from rhopalocerum by having the propodeal outline more 
evenly convex and more strongly convex immediately behind the metanotal groove. In exchao the 
propodeum behind the groove is more strongly raised in profile and passes through a much narrower curve 
into its posterior slope towards the declivity; compare Figs 77, 81. 

In the synonymy quoted above hottentota is given as provisional. This is because the type-series of 
rhopalocerum is based on workers and that of hottentota on females. I have not seen any samples which 
contain both females and workers but the overall marked similarity between these two short series, and the 
fact that both show the same data, leads me to suspect that they originated in a single series that was 
somehow later split up. M. leimbachi is an absolute synonym of rhopalocerum. 

Material examined 

South Africa: Cape Town (M. C. Day); Cape Town (G. Arnold); Cape Town (E. Simon); E. Cape 
Prov., Hogsback (W. L. Brown). 

Monomorium rosae Santschi 

Monomorium (Lampromyrmex) rosae Santschi, 19206: 13, figs 2c-f. Syntype workers, Zaire: Boma, 

7.ix.l913, No. 36 (Bequaert) (MRAC, NMB) [examined]. 
Diplomorium cotterelli Donisthorpe, 19426: 217. Holotype and paratype workers, Ghana: E. P., Tafo, 

xii.1940, No. 1370 (G. Cotterell) (BMNH) [examined]. Syn. n. 

Worker. TL 1-6-2-0, HL 0-42-0-50, HW 0-33-0-40, CI 76-82, SL 0-28-0-35, SI 85-94, PW 0-21-0-25, 
AL 0-42-0-56 (12 measured). 

Clypeal carinae only feebly developed but quite distinct, widely separated and divergent anteriorly. 
Median portion of clypeus with anterior margin transverse or even weakly convex, the anterior and lateral 
borders of the prominent median section of the clypeus meeting in an obtuse angle, without projecting 
angles or denticles. Basal (fourth) tooth of mandible much smaller than the third, reduced to a denticle. 
Maximum diameter of eye 0-19-0-23 x HW and with 5-6 ommatidia in the longest row. Outer ring of 
ommatidia encircling more than one longitudinal row. Eyes in full-face view distinctly in front of midlength 
of sides of head. Antennae with 11 segments, the scapes when directed straight back from their insertions 
failing to reach the occipital margin. Promesonotum in profile shallowly convex, the metanotal groove 
shallowly impressed and traversed by short but conspicuous cross-ribs. Propodeal spiracle small and 
pinhole-like. Propodeal dorsum in profile convex immediately behind the metanotal groove; this followed 
by a posteriorly sloping section which is feebly convex or almost flat, and which rounds posteriorly into the 
much more steeply sloping declivity. Petiole in profile with the node subconical, broad basally and rapidly 
tapering to a narrowly rounded apex; the node bluntly wedge-shaped. Subpetiolar process a narrow, 
sometimes vestigial , longitudinal strip ; ventral outline of petiole node behind the process feebly convex but 
not strongly bulging ventrally. Node of postpetiole in profile about equal in volume to that of the petiole, or 
slightly less; much more broadly rounded dorsally than the petiole. Anterior face of postpetiole in profile 
shorter and conspicuously steeper than the long gradually sloping posterior face. In dorsal view both nodes 
broader than long. Standing hairs present on all dorsal surfaces of head and body, with 4-6 pairs on the 
promesonotum and 2-3 pairs on the propodeum. Sculpture absent except for metanotal cross-ribs and 
some shagreening or reticulation on the pleurae. Colour glossy blackish brown to black. 

A widely distributed species which shows variation in size and pilosity over its range. Analysis of rosae 
when more material is available may well show that 2-3 sibling species are involved here. For the present 
all samples are treated as a single species, easily identified by its 11-segmented antennae, dark colour, 
moderately long scapes and distinctively shaped postpetiole node (as Fig. 92). The shape of the postpetiole 



SOLENOPSIS GENUS-GROUP 409 

is shared only with pulchrutn and bequaerti among species with 1 1 antennal segments, but both of these are 
lighter in colour. Apart from this the petiole and postpetiole nodes are broader than long in dorsal view in 
rosae and pulchrum, but longer than broad in bequaerti. M. pulchrutn has the propodeal dorsum quite 
evenly and continuously convex in profile, which is not the case in rosae where a flattened or depressed 
mid-dorsal section is conspicuous. 

The two syntype workers of rosae are lighter in colour than all the remaining material examined, but I 
strongly suspect that they had not attained full adult colour when captured, and have faded somewhat since 
then. 

Material examined 

Senegal: Noto (C. Agbogba). Ghana: Tafo (G. F. Cotterell); Tafo {B. Bolton); Mole (/. C. Grieg); 
Mampong (P. Room); Maase (D. Leston); Legon (D. Leston). Nigeria: Gambari (B. Bolton); Gambari 
(B. Taylor); Ibadan (B. Critchley); Mokwa (C Longhurst). Zaire: Boma (Bequaert); Luhoho, Riv. 
Bunyakiri (E. S. Ross & R. E. Leech). Kenya: Embu (V. Mahnert & J.-L. Perret). 

Monomorium rotundatum Santschi 

Monomorium {Lampromyrmex) rotundatum Santschi, 1920ft: 14, fig. 2a. Syntype workers, South Africa: 
Natal, Durban, 4.V.1914, ex coll. Arnold (H. B. Marley) (NMB) [examined]. 

Worker. TL 1-7-2-0, HL 0-44-0-48, HW 0-34-0-38, CI 77-81, SL 0-28-0-30, SI 79-83, PW 0-20-0-24, 
AL 0-44-0-52 (8 measured). 

Clypeal carinae narrowly but quite strongly developed, divergent anteriorly. Anterior clypeal margin 
transverse to shallowly convex between the anterior points of the clypeal carinae. Eyes relatively small, 
their maximum diameter 0-18-0-19 X HW. Eye in profile seen to consist of an outer ring of ommatidia 
which encircles a single short longitudinal row, the encircled row of only 2-3 ommatidia so that the eye is 
only slightly longer than high. In full-face view the eye conspicuously in front of the midlength of the sides 
of the head. Antennal scapes, when laid straight back from their insertions, failing to reach the occipital 
margin. Promesonotum only shallowly convex in profile, the metanotal groove weakly and shallowly 
impressed. Propodeal spiracle small and pinhole-like. Petiole with a short stout anterior peduncle. 
Subpetiolar process a longitudinal strip which narrows posteriorly until it runs into the convex ventral 
border of the petiole node itself. Node of petiole low and broadly subconical in profile, bluntly rounded 
dorsally. Postpetiole smaller than petiole and dorsally much more broadly and shallowly convex. Standing 
pilosity sparse, showing signs of abrasion in all material examined, but apparently with 4-5 pairs on the 
promesonotum and a single pair on the propodeum. Sculpture absent except for short but distinct 
metanotal cross-ribs. Colour yellow, the apex of the first gastral tergite traversed by a band of brown, which 
may be indistinct in older samples. 

In the original description Santschi placed rotundatum in the spurious subgenus Lampromyrmex , thus 
implying that the antennae had 11 segments. The antennae are poorly displayed in the three extant 
syntypes of this species, but those which are visible show 12 segments. 

Of the six known African species which combined 12-segmented antennae with the characteristic form of 
eye described above, rotundatum is diagnosed by its pilosity, colour, eye size and scape length. Com- 
parative measurements of the six species are as follows. 





HW 


CI 


SI 


Diameter of eye 


floricola 


0-33-0-37 


75-80 


86-94 


0-21-0-24 x HW 


shilohense 


0-30-0-34 


77-81 


80-85 


0-23-0-24 x HW 


sryetum 


0-32 


76 


84 


0-25 x HW 


inquietum 


0-38 


83 


76-79 


0-16 xHW 


rotundatum 


0-34-0-38 


77-81 


79-83 


0-18-0-19 x HW 


trake 


0-30 


79 


73 


0-17-0-18 xHW 



A single specimen from Kenya (in MCZ) is tentatively placed in rotundatum as all salient features match 
those of the South African material seen, but the petiole and postpetiole of the Kenyan specimens are 
obscured by glue. 

Material examined 
South Africa: Natal, Durban (//. B. Marley); Durban (C. B. Cooper). 



410 B. BOLTON 

Monomorium schultzei Forel 

Monomorium schultzei Forel, 1910c: 18. Syntype workers, female, South Africa: Cape Prov. (Klein- 
Namaland), Steinkop (L. Schultze); Namibia: Prince of Wales Bay, Angra Pequena (L. Schultze) 
(MHN) [examined]. 

Worker. TL 2-0-2-2, HL 0-54-0-58, HW 0-42-0-46, CI 77-80, SL 0-42-0-46, SI 97-102, PW 0-25-0-30, 
AL 0-54-0-60 (10 measured). 

Clypeal carinae sharply developed, close together and subparallel, at most only weakly divergent 
anteriorly. Area of clypeus between the carinae concave and the anterior clypeal margin between the 
apices of the carinae concave. Prominent median section of clypeus narrow, its anterior and lateral margins . 
separated by an angle which may be sharp, but without projecting denticles. Eyes relatively large, 
maximum diameter 0-24-0-27 x HW and with 7-8 ommatidia in the longest row. In full-face view the 
posterior margins of the eyes at the midlength of the sides of the head. Antennal scapes, when laid straight 
back from their insertions, just reaching the occipital margin. Sides of head behind eyes shallowly convex, 
the occipital margin broadly and shallowly concave. Major features of head very similar to that of 
excensurae, Fig. 61. Promesonotum in profile convex, its highest point in front of the promesonotal 
midlength and on a much higher level than the propodeum. Mesonotum sloping posteriorly and its outline 
almost flat. Metanotal groove very narrow and only feebly impressed, traversed by short and incon- 
spicuous cross-ribs. Propodeal dorsum sloping posteriorly, the spiracle minute and pinhole-like. Petiole in 
profile with an elongate narrow peduncle which is subtended by a small lobiform anteroventral process. 
Node of petiole narrow and subconical, narrowly rounded above. Postpetiole smaller, lower and more 
broadly rounded than petiole. In general the shape of the petiole and postpetiole is similar to that seen in 
excensurae (Fig. 75) but the subpetiolar process is smaller and the node slightly narrower. Viewed from 
above the dorsal surfaces of both nodes are distinctly broader than long. All dorsal surfaces of head and 
body with standing hairs, the promesonotum with 5-6 pairs. Sculpture absent except for scattered minute 
hair-pits, the feeble metanotal cross-ribs and some meso- and metapleural vestiges. Colour predominantly 
yellow but the cephalic dorsum and gastral tergites duller and with a pale brownish yellow tint in some. 

M. schultzei is closest related to excensurae and bevisi. The last named is a larger and more densely hairy 
species, and it is also distinctly darker in colour. Differences between schultzei and excensurae are 
discussed under the latter name. 

Material examined 

South Africa: Cape Prov. , Lower Albany, Grahamstown (J. Hewitt); Grahamstown (G. Baines & E. M. 
Cherry); Steinkop (L. Schultze). Namibia: Angra Pequena (L. Schultze). Lesotho: Roma (R. L. Ghent). 

Monomorium shilohense Forel stat. n. 

Monomorium braunsi var. shilohensis Forel, 1913c: 217. Syntype workers, Zimbabwe: Shiloh, 10. v. 1913, 
no. 173 (G. Arnold) (BMNH; MHN) [examined]. 

Worker. TL 1-5-1-6, HL 0-38-0-44, HW 0-30-0-34, CI 77-81, SL 0-24-0-28, SI 80-85, PW 0-19-0-23, 
AL 0-42-0-46 (5 measured). 

Anterior clypeal margin transverse to feebly concave between the apices of the weakly developed 
clypeal carinae, the latter distinctly divergent anteriorly but not terminating in teeth or projecting angles. 
Instead the anterior margin and lateral margins of the projecting median section of the clypeus meet in 
obtuse angles. Maximum diameter of eye 0-23-0-24 x HW. In profile the eye conspicuously longer than 
high, the ommatidia arranged as an outer ring which encircles a single inner longitudinal row. The encircled 
row consists usually of 3 ommatidia but rarely 4 may be present. In full-face view the eyes distinctly in front 
of the midlength of the sides and the scapes, when laid straight back from their insertions, fail to reach the 
occipital margin. Promesonotum shallowly convex, almost flat posteriorly , sloping to the metanotal groove 
which is shallow and almost unimpressed. Propodeal dorsum continues the slope of the posterior 
mesonotum and the propodeal spiracle is minute and pinhole-like . Peduncle of petiole short and subtended 
by a short but deep and conspicuous process. Petiole node low and broadly subconical, its ventral surface 
distinctly bulging and convex; the subpetiolar process is confluent with this bulge. Postpetiole low and 
rounded, smaller than the petiole. All available specimens are abraded but the promesonotum apparently 
has 3-4 pairs of standing hairs and the propodeum one pair. The head, petiole, postpetiole and gaster also 
have standing hairs present. Head and body without sculpture except for metanotal cross-ribs and some 
weak granular sculpture on the mesopleuron. Colour yellow throughout, the apical half of the first gastral 
tergite without a transverse brown band. 



SOLENOPSIS GENUS-GROUP 411 

One of only six species in the region to combine 12-segmented antennae with the characteristic eye form 
described above. M. shilohense is separated from the other five by its colour, the shape and size of its eyes, 
and its pilosity. In sryetum the dorsal alitrunk has only a single pair of standing hairs, at the pronotal 
humeri, whilst all the others have more than one pair. M. trake and rotundatum have small eyes 
(0-17-0-19 x HW as opposed to 0-21-0-25 x HW elsewhere) which appear almost circular in profile, being 
only fractionally longer than high rather than distinctly elongate and narrow as seen in the remaining four 
species. In inquietum and trake the anterior clypeal margin is evenly convex, lacking the differentiated 
prominent median portion developed by the other four species. In floricola and inquietum the head is 
conspicuously brown in colour, whereas it is yellow in the remaining four species. 

Material examined 
Zimbabwe: Shiloh (G. Arnold); Hillside, Bulawayo (G. Arnold). 

Monomorium spectrum sp. n. 

Holotype worker. TL 1-3, HL 0-34, HW 0-28, CI 82, SL 0-22, SI 79, PW 017, AL 0-36. 

Median portion of clypeus distinctly projecting anteriorly, its anterior margin transverse to extremely 
feebly concave and separated from the lateral margins by an obtuse angle; the margin lacking projecting 
angles or teeth where they meet. Clypeal carinae only weakly developed, almost effaced, widely separated 
and divergent anteriorly. Maximum diameter of eye 0-21 x HW, in profile the eye consisting of an outer 
ring of ommatidia which encloses a single transverse row of only two ommatidia; the maximum diameter of 
the eye with 4 ommatidia in the only longitudinal row. Eyes in full-face view distinctly in front of the 
midlength of the sides. Antennae with 11 segments. Antennal scapes, when laid straight back from their 
insertions, failing to reach the occipital margin. Promesonotum in profile having an evenly convex low but 
broad dome-like outline. Metanotal groove distinctly impressed, traversed by short but conspicuous 
cross-ribs. Propodeal dorsum convex but its highest point on a much lower level than that of the 
promesonotum, the dorsum rounding very broadly and evenly into the posteriorly sloping declivity. 
Propodeal spiracle small, not dominating the side of the sclerite. Petiole with a short and quite stout 
anterior peduncle which is subtended by a small longitudinal ventral process. Ventral outline of node 
behind level of process conspicuously convex. Petiole node bluntly subconical in profile, larger than the 
postpetiole but the latter somewhat more broadly rounded above. All dorsal surfaces of body with standing 
hairs present, the promesonotum with 5-6 pairs. Sculpture absent except for metanotal cross-ribs. Head 
and body a uniform rich dark brown, the legs extremely pale, off-white to bone-white and contrasting very 
strongly with the body. 

Paratype workers. TL 1-2-1-3, HL 0-32-0-36, HW 0-26-0-29, CI 80-82, SL 0-20-0-22, SI 76-79, PW 
0-16-0-18, AL 0-34-0-37 (10 measured). As holotype but maximum diameter of eye 0-19-0-21 x HW. 

Holotype worker, Gabon: Makokou, x.1972 (/. Lieberburg) (MCZ). 

Paratypes. Gabon: 8 workers with same data as holotype; 4 workers, Plateau d'Ipassa 9, IPA AN4(7. A. 
Barra) (MCZ; BMNH). 

Among the Afrotropical species with 1 1-segmented antennae the distinctive and striking colour contrast 
between body and legs makes spectrum immediately recognizable. 

Monomorium speluncarum Santschi stat. n. 

Monomorium rhopalocerum st. speluncarum Santschi, 1914a: 72, fig. 6. Syntype workers, Kenya: 
Shimoni, st. no. 9, xi.1911, 'entree de la grotte A' (Alluaud & Jeannel) (NMB) [examined]. 

Worker. TL 1-6-1-7, HL 0-40-0-42, HW 0-31-0-32, CI 75-76, SL 0-33-0-34, SI 106-107, PW 0-20-0-22, 
AL 0-42-0-44 (3 measured). 

Clypeal carinae fine and sharp, close together and subparallel, only slightly divergent anteriorly. 
Prominent median portion of clypeal margin narrow, its anterior margin separated from its lateral margins 
only by blunt to rounded angles; without projecting angles or denticles. Maximum diameter of eye 
0-22 x HW and with 4-5 ommatidia in the longest row. With the head in full-face view the eyes situated 
just in front of the midlength of the sides , the posterior margins of the eyes approximately at the midlength . 
Antennal scapes, when laid straight back from their insertions, reaching the occipital margin; the scapes 
relatively long, SI > 105. Occipital margin of head broad and shallowly concave in full-face view, the sides 
very feebly convex. Promesonotal dorsum evenly convex in profile, high, on a much higher level than the 



412 B. BOLTON 

propodeum. Extreme posterior portion of mesonotum suddenly downcurved and descending steeply to the 
broad, deep, strongly cross-ribbed metanotal groove. Propodeal dorsum short and rounding abruptly into 
the declivity, the two surfaces about equal in length. Propodeal spiracle minute, pinhole-like. Petiole node 
large and broadly subconical, narrowly rounded above. Postpetiole smaller and lower than petiole, more 
broadly and evenly rounded. All dorsal surfaces of head and body with standing hairs, the promesonotum 
with 4 pairs and the propodeum with 2 pairs. Sculpture restricted to faint granulation on the mesopleuron 
and the long strong cross-ribs of the metanotal groove, remainder of body smooth and featureless except 
for hair-pits. Colour uniform pale yellow. 

Within the schultzei-complex speluncarum , apart from being the smallest known species, has the unique 
combination of minute spiracle and broad metanotal groove. In the complex the various combinations of 
these two characters are as follows. 

Propodeal spiracle large and dominating the sclerite, plus metanotal groove broad and traversed by long 
strong cross-ribs: arboreum, vecte, craw ley i,firmum, kineti (Figs 64, 65, 67-69). 

Propodeal spiracle minute and pinhole-like, plus metanotal groove very narrow and traversed by short 
feeble cross-ribs: bevisi, excensurae, schultzei (Fig. 75). 

Propodeal spiracle minute and pinhole-like, plus metanotal groove broad and traversed by long strong 
cross-ribs: speluncarum. 

Material examined 

Kenya: Shimoni (Alluaud & Jeannel). 

Monomorium springvalense Forel 

Monomorium oscaris r. springvalense Forel, 1913£>: 136. Syntype workers, Zimbabwe: Springvale 
6.X.1912, no. Ill (G. Arnold) (BMNH; MHN) [examined]. 

Monomorium (Monomorium) springvalense Forel; Santschi, 1937: 225. [Raised to species.] 

Worker. TL 2-0-2-1, HL 0-50-0-52, HW 0-40-0-41, CI 77-80, SL 0-36-0-37, SI 90, PW 0-26-0-30, 
AL 0-53-0-58. 

Clypeal carinae sharply developed and conspicuous; widely divergent anteriorly. Anterior margin of 
prominent median portion of clypeus transverse to shallowly concave, usually with a feebly crenulate 
appearance. The anterior margin is bounded on each side by a low triangular prominent angle at the apex 
of each clypeal carina, the projecting angle separating the anterior and lateral margins of the median 
portion of the clypeus. Maximum diameter of eye 0-22-0-23 x HW and with 6-7 ommatidia in the longest 
row. Antennal scapes, when laid straight back from their insertions, failing to reach the occipital margin. 
With the head in full-face view the eyes situated conspicuously in front of the midlength of the sides; the 
sides behind the eyes weakly convex and the broad occipital margin shallowly concave medially. 
Promesonotum evenly shallowly convex in profile, sloping posteriorly to the narrow and only weakly 
impressed metanotal groove. Metanotal cross-ribs short but distinct. Propodeal spiracle of moderate size, 
not reduced to a mere pinhole nor very large and dominating the side of the sclerite. Propodeal dorsum 
rounding broadly and evenly into the declivity. Subpetiolar process a small anteroventral lobe which peters 
out posteriorly. Node of petiole in profile quite thickly subconical, the anterior and posterior faces both 
very fully convex and the node bluntly rounded above. Postpetiole smaller and lower than petiole, more 
broadly rounded dorsally but with relatively steep anterior and posterior faces, both of which are nearly 
vertical. Standing hairs present on all dorsal surfaces but relatively sparse on the alitrunk; the promeso- 
notum with only 4 pairs. Sculpture entirely absent except for scattered hair-pits and metanotal cross-ribs. 
Alitrunk yellow, the head and gaster with a brownish tint; usually the gaster slightly darker in shade than 
the head. 

M. springvalense is very closely related to borlei within the leopoldinum-complex but the two are 
separated by the darker colour, larger propodeal spiracle and even sparser pilosity of the latter. 

Material examined 

Zimbabwe: Springvale (G. Arnold). 



SOLENOPSJS GENUS-GROUP 413 

Monomorium sryetum sp. n. 

Holotype worker. TL 15, HL 0-42, HW 0-32, CI 76, SL 0-27, SI 84, PW 0-21, AL 0-44. 

Median portion of clypeus with its anterior margin transverse between the apices of the clypeal carinae, 
the latter weakly developed but strongly divergent anteriorly. Anterior and lateral margins of projecting 
median portion of clypeus meeting in obtuse angles, without prominent denticles where they meet. 
Maximum diameter of eye 0-25 x HW. In profile the eye elongate and narrow, conspicuously much longer 
than high. Ommatidia of eye arranged as an outer ring which encloses a single longitudinal inner row of 3 
ommatidia. In full-face view the eyes distinctly far in front of the midlength of the sides. Scapes, when laid 
straight back from their insertions, markedly failing to reach the concave occipital margin. Promesonotum 
shallowly convex in profile and on a higher level than the propodeum. Metanotal groove not impressed. 
Propodeal spiracle small but conspicuous. Petiole with a short anterior peduncle which is subtended by an 
elongate and distinct strip-like ventral process. Petiole node low and bluntly subconical, the ventral margin 
bulging and convex behind the end of the subpetiolar process. Postpetiole smaller than petiole, its node 
only slightly more broadly rounded than that of the petiole. Dorsum of head with sparse standing hairs 
which are mostly confined to the occipital margin. Dorsal alitrunk with a single pair of standing hairs, 
situated at the pronotal humeri. Petiole and postpetiole each with a single pair of hairs but first gastral 
tergite with standing hairs evenly distributed. Sculpture absent except for very short and weakly developed 
cross-ribs traversing the metanotal groove. Colour very pale yellow, the gaster whitish yellow; no trace of 
brown anywhere on the head or body. 

Holotype worker, Botswana: Maxwee, mopane woodland, ll.ii.1976, no. 38 (A. Russell-Smith) 
(BMNH). 

This minute species is rendered very distinctive by the combination of its eye form, 12-segmented 
antennae, and extremely reduced alitrunk pilosity . The form of the eye described above is shared with only 
five other Afrotropical species in which the antennae have 12 segments, but all of these (inquietum, 
rotundatum,floricola, shilohense, trake) have more than one pair of standing hairs on the alitrunk. Also, 
the eyes of rotundatum and trake are small (0-17-0T9 x HW) and almost circular, whilst mfloricola and 
inquietum the head is brown in colour. 

Monomorium strangulatum Santschi 

Monomorium strangulatum Santschi, 19216: 121, fig. 3. Lectotype worker, Tanzania: Bukoba, Bezirk, 
Buk. 26 (Viehmeyer) (NMB) (here designated) [examined]. 

Note. The two worker syntypes originally mounted on a single pin and constituting the type-series of 
strangulatum belong to two separate species. The upper specimen, which fits Santschi's original description 
the best, is here designated as the lectotype of strangulatum, and has 11 antennal segments. The lower 
specimen has been removed to a separate pin and now constitutes the holotype of disoriente; this species 
has 12 antennal segments. 

Worker. TL 1 -8-2-0, HL 0-41-0-46, HW 0-33-0-38, CI 78-83, SL 0-32-0-38, SI 95-102, PW 0-20-0-26, 
AL 0-48-0-58 (10 measured). 

Clypeal carinae sharply developed, widely separated and feebly divergent anteriorly, the carinae 
running to the anterior margin at the angle separating the anterior and lateral margins of the projecting 
median portion of the clypeus. Space between the clypeal carinae very shallowly transversely concave. 
Maximum diameter of eye 0-22-0-26 x HW and with 5 ommatidia in the longest row. In full-face view the 
posterior margins of the eyes at the midlength of the sides. Antennae with 11 segments and the scapes, 
when laid straight back from their insertions, surpassing the occipital margin. Sides of head behind eyes 
convex in full-face view, converging posteriorly and meeting the occipital margin through a broad 
continuous curve on each side, so that the transverse median portion of the occipital margin appears very 
short. Promesonotum domed-convex in profile, on a much higher level than the propodeum. Mesonotum 
forming a convex slope posteriorly to the very broadly but shallowly impressed metanotal groove, the latter 
with conspicuous strong cross-ribs. Propodeum behind the metanotal groove convex and sloping pos- 
teriorly, joining the declivity through a broad curve. Propodeal spiracle large, dominating the side of the 
sclerite. Petiole with an elongate but stout anterior peduncle which is subtended by an inconspicuous 
ventral process in the form of a narrow cuticular strip. Petiole node large, high and subconical, narrowly 
rounded above. Node of postpetiole anteroposteriorly compressed, narrow in profile, with a steeply 
sloping anterior face. All dorsal surfaces of head and body with numerous standing hairs, the scapes with 



414 B. BOLTON 

long suberect to subdecumbent pubescence which is almost as long as the maximum width of the scape. 
Head and body unsculptured except for hair-pits, metanotal cross-ribs and extensive reticulate-punctate to 
reticulate-granulate sculpture on the mesopleuron. Head and body dark brown, the appendages yellow 
and contrasting strongly with the body colour. 

Despite its 11-segmented antennae the closest relatives of strangulation are the 12-segmented draxocum, 
noxitum and gabrielense . 

Material examined 

Gabon: Plateau d'Ipassa (/. A. Barra). Central African Republic: Ubangi-Shari, Haut Mbomu (N. A. 
Weber). Uganda: Sese Is., Nkosi I. (G. D. H. Carpenter). Tanzania: Bukoba, Bezirk (Viehmeyer). Zaire: 
Ituri Forest, Beni-Irumu (N. A. Weber). 

Monomorium symmotu sp. n. 

(Fig. 79) 

Holotype worker. TL 1-9, HL 0-52, HW 0-39, CI 75, SL 0-35, SI 90, PW 0-25, AL 0-56. 

Clypeal carinae distinct, close together and only weakly divergent anteriorly. Space between the clypeal 
carinae almost transversely flat, only extremely feebly concave. Anterior clypeal margin between apices of 
the carinae extremely feebly concave, almost transverse. Anterior margin of prominent median portion of 
clypeus rounding bluntly into lateral margins, the two not separated by sharp angles or projecting 
denticles. Maximum diameter of eye 0-21 x HW and with 6 ommatidia in the longest row. In full-face view 
the posterior margins of the eyes conspicuously in front of the midlength of the sides. Antennal scapes, 
when laid straight back from their insertions, failing to reach the occipital margin. Sides of head behind 
eyes shallowly convex and feebly convergent posteriorly, the occipital margin distinctly concave medially. 
Promesonotum in profile evenly convex and on a higher level than the propodeum. Posteriormost portion 
of mesonotum suddenly downcurved and descending steeply to the broad and deeply impressed metanotal 
groove. Metanotal cross-ribs strong and conspicuous; propodeal spiracle small. Propodeal dorsum in 
profile evenly convex, highest behind metanotal groove; the dorsum and declivity rounding broadly and 
evenly together so that they form a single convex curve. Node of petiole low and broad in profile, broadly 
rounded above; in dorsal view the node subglobular. Antero- ventral process of petiole peduncle a narrow 
cuticular strip. Postpetiole in profile smaller than petiole, lower and much more broadly rounded dorsally. 
All dorsal surfaces of head and body with standing hairs but these are relatively sparse ; only 3 pairs present 
on the promesonotum. Sculpture absent except for scattered hair-pits and metanotal cross-ribs; the 
mesopleuron with some faint sculptural vestiges at about its midlength. Colour yellow. 

Paratype workers. TL 1-8-1-9, HL 0-48-0-52, HW 0-36-0-39, CI 74-76, SL 0-34-0-35, SI 89-94, PW 
0-23-0-25, AL 0-52-0-56 (8 measured). Maximum diameter of eye 0-20-0-23 x HW and with 5-6 
ommatidia in the longest row. Otherwise as holotype. 

Holotype worker, Zimbabwe (Rhodesia on label): Vumba Mts, nr Umtali, 11. hi. 1969 (W. L. Brown) 
(MCZ). 
Paratypes, 19 workers with same data as holotype (MCZ; BMNH). 
Non-paratypic material examined. Zimbabwe: Umtali, Melsetter (R. Mussard). 

A small member of the rhopalocerum-complex, symmotu most closely resembles exchao. The two are 
separated by their differently shaped alitrunk and petiole outlines (Figs 77, 79) and by the presence in 
symmotu of only 3 pairs of standing hairs on the promesonotal dorsum. Further notes are given under 
rhopalocerum. 

Monomorium tablense Santschi stat. n. 

(Fig. 80) 

Monomorium altinode st. tablensis Santschi, 1932: 384, figs 6, 7. Syntype workers, female, South Africa: 
Cape Prov., Table Mt, 28.xii.1913 (G. Arnold) (NMB) [examined]. 

Worker. TL 2-1-2-2, HL 0-52-0-54, HW 0-40-0-42, CI 77-78, SL 0-39-0-40, SI 95-98, PW 0-26-0-27, 
AL 0-54-0-56 (2 measured). 



SOLENOPSIS GENUS-GROUP 415 

Projecting median portion of clypeus with its anterior margin and lateral margins separated by blunt 
angles, without projecting prominences or denticles. Clypeal carinae weakly divergent anteriorly. Maxi- 
mum diameter of eye 0-24-0-25 x HW and with 6-7 ommatidia in the longest row. With the head in 
full-face view the posterior margins of the eyes distinctly in front of the midlength of the sides and the 
antennal scapes, when laid straight back from their insertions, failing to reach the occipital margin. 
Occipital margin of head broad and shallowly concave, the sides very weakly convex in full-face view. 
Promesonotum convex in profile, sloping posteriorly to the narrow and shallowly impressed metanotal 
groove. Propodeal spiracle small, the dorsal surface of the segment sloping posteriorly and separated from 
the declivity by a very obtuse bluntly rounded angle. Petiole node very narrow in profile, high and with its 
anterior face evenly shallowly concave, posterior face of node weakly convex. Postpetiole node smaller 
and rounded. Subpetiolar process a small ridge or lobe. Head and alitrunk of both extant syntypes very 
abraded and probably showing less hair than was originally present. Promesonotum with 2 pairs of hairs; 
probably more in fresh specimens. Metanotal groove with short fine cross-ribs and mesopleuron with 
vestiges of granulate or reticulate sculpture, but otherwise the entire body smooth and unsculptured. 
Colour brownish yellow to light brown. 

Originally described as a stirps of altinode, because of the shape of the petiole node, tablense is really 
related to rhopalocerum and its allies, but is separated from any other species of this complex by its 
strangely shaped petiole (Fig. 80) and large eyes. Of the allies of rhopalcerum, binatu approaches tablense 
most closely in node shape, but in binatu the scapes are longer (SI 100-103) and reach the occipital margin, 
and the metanotal groove is much broader and more deeply impressed. 

Material examined 
South Africa: Table Mt (G. Arnold). 

Monomorium taedium sp. n. 

Holotype worker. TL 1-7, HL 0-46, HW 0-38, CI 83, SL 0-31, SI 82, PW 0-25, AL 0-49. 

Clypeal carinae conspicuous, close together posteriorly and widely divergent anteriorly. Anterior 
margin of prominent median portion of clypeus transverse to exceptionally feebly convex, the anterior 
margin meeting the sides in an obtuse angle but lacking projecting sharp angles or denticles. Maximum 
diameter of eye 0-21 x HW, with 6 ommatidia in the longest row. With the head in profile the eye almost as 
high as long and the outer ring of ommatidia enclosing three longitudinal rows, unlike most other members 
of the shilohense-comp\ex where the outer ring of ommatidia only encloses a single longitudinal row of 2-4 
ommatidia. In full-face view the eyes conspicuously in front of the midlength of the sides of the head. 
Antennae with 11 segments. Antennal scapes, when laid straight back from their insertions, failing to reach 
the occipital margin Promesonotum in profile feebly convex and forming a long shallow slope back to the 
broadly impressed metanotal groove; the latter with conspicuous cross-ribs. Propodeal dorsum highest 
immediately behind the metanotal groove, sloping downwards posteriorly and rounding broadly and 
evenly into the declivity. Propodeal spiracle small. Petiole with a short narrow anterior peduncle which has 
a very small anteroventral process. Ventral outline of petiole markedly concave from process to level of the 
spiracle, behind which it is markedly convex beneath the node proper. Petiole node in profile bluntly 
subconical and rounded above, the postpetiole slightly smaller but much more broadly rounded dorsally. 
All dorsal surfaces of head and body with standing hairs, the promesonotum with 3-4 pairs but the 
pronotum lacking a pair on the anterior margin between the humeral pair. Sculpture absent except for 
metanotal cross-ribs and some faint punctulate areas on the mesopleuron. Colour glossy medium brown. 

Paratope workers. TL 1-6-1-7, HL 0-42-0-47, HW 0-34-0-38, CI 80-83, SL 0-28-0-31, SI 80-83, PW 
0-23-0-26, AL 0-44-0-49 (7 measured) . As holotype but some lighter brown in colour. Maximum diameter 
of eye 0-19-0-22 X HW, the outer ring of ommatidia enclosing three longitudinal rows as in the holotype , 
or enclosing two rows plus one or two other ommatidia; with 5-6 ommatidia in the longest row. 

Holotype worker, South Africa: Natal, Umlalazi Nat. Res., 25.iii.1979 (D. J. Brothers) (BMNH). 
Paratypes. 7 workers with same data as holotype (BMNH; MCZ). 

The type-series was recovered from a sample of leaf litter. Among the Afrotropical species with only 11 
antennal segments taedium is isolated by its relatively large eyes, dark colour, size, and lack of an enlarged 
and characteristically shaped postpetiole such as is seen in bequaerti and its allies. Like mictilis and 
fastidium, taedium also lacks a pair of standing hairs on the anterior margin of the pronotum between the 
humeral pair, but taedium is larger than either of these and has many more ommatidia in the eye. 



416 B. BOLTON 

Monomorium tanysum sp. n. 

Holotype worker. TL 15, HL 0-42, HW 0-34, CI 81, SL 0-30, SI 88, PW 0-22, AL 0-46. 

Clypeal carinae sharply developed and conspicuous, widely separated and subparallel posteriorly, 
feebly divergent anteriorly. Space between the clypeal carinae flat to shallowly transversely concave. 
Anterior clypeal margin transverse between the apices of the carinae. Anterior and lateral margins of 
prominent median portion of clypeus separated by blunt obtuse angles, without denticles or projecting 
acute angles. Clypeal carinae meeting anterior margin medially of the obtuse angles separating the anterior 
and lateral margins, each carina paralleled externally by a weak rugule which runs back from the angle to 
the antennal socket. Maximum diameter of eye 0-18 x HW and with 6 ommatidia in the longest row. In 
full-face view the eyes just in front of the midlength of the sides. Antennal scapes, when laid straight back 
from their insertions, failing to reach the occipital margin. Sides of head weakly convex in full-face view, 
slightly convergent both in front of and behind the eyes. Occipital margin with a short shallow median 
indentation. Head in profile distinctly biconvex, deepest at about the midlength. Promesonotum a low 
domed convexity in profile, highest at its midlength and distinctly on a much higher level than the 
propodeum. Metanotal groove shallowly impressed but broad, traversed by strong cross-ribs dorsally; 
laterally the cross-ribs are less distinct and become confused with the strong mesopleural sculpture. 
Propodeal spiracle small, the propodeal dorsum highest immediately behind the metanotal groove. 
Posterior to this the outline is almost flat in profile and sloping at about 45° until it rounds into the very short 
declivity through a blunt angle. In dorsal view the posterior half of the propodeum is almost flat 
transversely. Petiole in profile with a short anterior peduncle which is subtended by a short but deep 
anteroventral process. Petiole node high and subcorneal, narrowly rounded above. Postpetiole lower than 
petiole, more bluntly rounded above and with its anterior face nearly vertical, distinctly steeper than the 
posterior face. All dorsal surfaces of head and body with standing hairs, the promesonotum with 5 pairs. 
Unsculptured except for hair-pits, metanotal cross-ribs and reticulate-punctation on the mesopleuron. 
Colour brown, the gaster darker than the alitrunk and almost blackish brown. 

Paratype worker. TL 1-6, HL 0-42, HW 0-38, CI 83, SL 0-30, SI 86, PW 0-22, AL 0-46. 

As holotype but maximum diameter of eye 0- 17 x HW and the anterior margin of the prominent median 
section of the clypeus shallowly concave. 

Holotype worker, Ghana: Mampong, 17. xi. 1969 (P. Room) (BMNH) 
Paratype, 1 worker with same data as holotype (BMNH). 

The Ghanaian tanysum is related most closely to the Tanzanian disoriente, the two sharing a very similar 
outline shape of alitrunk (Fig. 83). In tanysum, however, the ventral process of the petiole is shorter and 
deeper and the postpetiole node higher and narrower than is indicated in disoriente. Apart from this the 
eyes are distinctly larger in disoriente (0-24 x HW) and the scapes relatively longer (SI 92). M. tanysum and 
disoriente together are closest to dolatu, a form with only 11-segmented antennae. Overall appearance is 
very similar in all three but dolatu has a more strongly tapered petiole node which is very narrowly rounded 
above, and approaches the distinctly cuneate node form of affabile and malatu. M. dolatu is yellow in 
colour and has the eyes somewhat further forward on the side than either tanysum or disoriente. In affabile 
and malatu the propodeum is reticulate-punctate everywhere, a condition not present in any of the 
foregoing species. 

Monomorium torvicte sp. n. 

Holotype worker. TL 1-5, HL 0-45, HW 0-34, CI 76, SL 0-27, SI 79, PW 0-20, AL 0-44. 

Clypeal carinae distinctly developed, relatively close together posteriorly and widely divergent an- 
teriorly, reaching the anterior clypeal margin. Prominent median portion of clypeus with its anterior 
margin transverse between the apices of the carinae, the anterior and lateral borders separated by an 
obtuse angle but lacking denticles or projections where the borders meet. Maximum diameter of eye 
0-21 x HW and with 6 ommatidia in the longest row. Eye in full-face view distinctly far in front of the 
midlength of the sides of the head. In profile the eye elongate-oval, its long axis noticeably greater than its 
vertical axis. Antennal scapes, when laid straight back from their insertions, conspicuously failing to reach 
the occipital margin. Sides of head shallowly convex in full-face view, broadest at about the midlength; 
occipital margin broad and broadly, shallowly concave. Head in profile dorsoventrally flattened. Cephalic 
dorsum of holotype dented but in paratypes the ventral surface of the head is flat to very shallowly convex, 
the dorsum only slightly more convex than the ventre in profile. Promesonotal dorsum evenly shallowly 
convex in profile, curving downwards posteriorly to the conspicuously impressed metanotal groove. 



SOLENOPSIS GENUS-GROUP 417 

Metanotal cross-ribs distinct. Propodeal spiracle small and the propodeal dorsal outline convex behind the 
metanotal groove. Propodeum on a lower level than highest point of promesonotum and posteriorly 
rounding broadly and evenly into the declivity. Anterior peduncle of petiole short and stout, subtended by 
a short narrow strip-like anteroventral process which is truncated anteriorly. Node of petiole relatively low 
and broad in profile, broadly rounded above and with about the same degree of convexity as the 
postpetiolar dorsum. Postpetiole smaller and lower than the petiole node. All dorsal surfaces of head and 
body with standing hairs present. All available material somewhat abraded but the promesonotum 
probably with 5 pairs of standing hairs, of which the pair at the pronotal humeri is the longest. Sculpture 
absent except for minute hair-pits and metanotal cross-ribs. Colour uniform dark brown. 

Paratype workers. TL1-5-1-6, HL 0-44-0-45, HW 0-33-0-35, CI 75-80, SL 0-25-0-28, SI 76-80, PW 
0-18-0-21, AL 0-42-0-45 (5 measured). Maximum diameter of eye 0-20-0-21 x HW. All specimens 
uniformly brown in colour but the shade varying from medium to dark. The lighter individuals may not 
have acquired full adult colour. 

Holotype worker, South Africa: Cape Town, vii.1912, ex coll. S.A. Museum, G. Arnold, no. 155 (on 
underside of card) (£. Phillips) (BMNH). 

Paratypes. 6 workers and 1 female mounted on same card (BMNH). Holotype is third from right and is 
indicated by a small directional arrow on the card. 

Closest related to mavide, another minute South African species. Differentiating characters of torvicte 
and mavide are given under the latter name. 

Monomorium trake sp. n. 

Holotype worker. TL 1-6, HL 0-39, HW 0-30, CI 77, SL 0-22, SI 73, PW 0- 19, AL 0-40. 

Mandible equipped with three strong teeth and a minute offset basal denticle. Anterior clypeal margin 
more or less evenly convex between the inner borders of the mandibles, without a strongly differentiated 
prominent median section. Clypeal carinae feebly developed, widely divergent anteriorly. Eye in profile 
small, its length only slightly greater than its height and the maximum diameter of the eye 0- 18 x HW. 
Ommatidia of eye arranged as an outer ring which surrounds a single longitudinal row, the encircled row 
consisting of only two ommatidia. In full-face view the eyes distinctly in front of the midlength of the sides. 
Antennal scapes relatively very short, SI < 75; when laid straight back from their insertions the scapes 
conspicuously failing to reach the occipital margin. Promesonotal dorsum evenly shallowly convex in 
profile, sloping posteriorly to the extremely feebly impressed metanotal groove. Propodeal spiracle small, 
pinhole-like. Node of petiole low and bluntly rounded dorsally, the anterior peduncle short and subtended 
by a strip-like ventral process which runs from close to the insertion to the strong posteroventral bulge of 
the petiole. Postpetiole smaller than petiole and only slightly more broadly rounded dorsally. Standing 
hairs present on all dorsal surfaces but everywhere sparse; the promesonotum with 5 pairs, the propodeum 
with a single pair. Sculpture absent except for short cross-ribs at the metanotal groove. Colour uniform 
yellow except for apex of first gastral tergite which is traversed by a band of brown. 

Paratype workers. TL 1-6, HL 0-38-0-39, HW 0-30, CI 77-79, SL 0-22, SI 73, PW 0-18-0-19, AL 
0-38-0-40 (3 measured). As holotype but maximum diameter of eye 0-17-0-18 x HW. Only one of the 
paratypes shows its full complement of alitrunk pilosity, the other two both show signs of abrasion. 

Holotype worker, Ghana: Aburi, 22.iii.1969 (P. Room) (BMNH) 
Paratypes. 3 workers with same data as holotype (BMNH; MCZ) 

One of only 6 species to combine 12-segmented antennae with the reduced form of eye described above, 
trake is isolated from the other five species sharing these characters by its very short antennal scapes , SI 73 . 
In the remaining species (shilohense, rotundatum, sryetum,floricola and inquietum) SI is >75, usually >80. 
Other differentiating characters are noted under the names of the other five species. 

Monomorium tynsorum sp. n. 

(Figs 62, 87) 

Holotype worker. TL 2- 1, HL 0-54, HW 0-42, CI 78, SL 0-38, SI 90, PW 0-28, AL 0-56. 
Clypeal carinae strongly developed and sharp, conspicuously divergent anteriorly and terminating on 



418 B. BOLTON 

the anterior margin in a pair of small projecting denticles. Space between the clypeal carinae transversely 
shallowly concave. Anterior margin of prominent median portion of clypeus transverse to extremely 
shallowly concave between the denticles. Maximum diameter of eye 0-24 x HW and with 7 ommatidia in 
the longest row. With the head in full-face view the posterior margins of the eyes in front of the midlength 
of the sides of the head. Antennal scapes, when laid straight back from their insertions, failing to reach the 
occipital margin. Sides of head shallowly convex behind the eyes and very feebly convergent posteriorly. 
Occipital margin broad and extremely weakly concave medially; almost transverse. Promesonotal dorsum 
evenly convex in profile, sloping posteriorly to the narrow but distinctly impressed metanotal groove. 
Metanotal cross-ribs short but conspicuous. Propodeal spiracle of moderate size, not reduced to a minute 
pinhole-like aperture. Propodeal dorsum shallowly convex and sloping posteriorly, rounding into the short 
but more steeply descending declivity. Petiole peduncle with a small low anteroventral process which 
extends back to the level of the spiracle. Petiole node high but somewhat thicker than in closely related 
species (compare Figs 84-88), narrowly rounded above. Postpetiole with a vertical anterior face to the 
node, smaller and somewhat narrower than the petiole, and more broadly rounded dorsally. All dorsal 
surfaces of head and body with standing hairs, the promesonotum with 7-8 pairs. Sculpture absent except 
for scattered minute hair-pits, metanotal cross-ribs and some faint vestiges on the mesopleuron. Colour 
yellow. 

Paratype workers. TL 2-1-2-3, HL 0-52-0-55, HW 0-40-0-44, CI 78-81, SL 0-37-0-40, SI 90-95, PW 
0-24-0-28, AL 0-54-0-60 (8 measured). As holotype but maximum diameter of eye 0-24-0-25 x HW. 

Holotype worker, Angola: Luanda, 24.viii.1949, from body of dead bird (G. R. Gradwell & D. Snow) 
(BMNH). 
Paratypes. 14 workers with same data as holotype (BMNH; MCZ). 

Of the presently recognized species in the altinode-complex two, occidentale and vonatu, are blackish 
brown or black in colour and have unique clypeal and petiolar configurations respectively. The remainder, 
altinode, angustinode, arnoldi, captator, fugelanum and tynsorum, are yellow and lack the clypeal and 
petiolar specializations seen in the above. M. angustinode has a very distinctive form of propodeum and 
tubercle-borne spiracle which separates it from the remainder, and the propodeal spiracle is conspicuously 
enlarged in the densely hairy captator. The four remaining species are very closely related and details of 
their separation are given under altinode. 

Monomorium vaguum Santschi 

Monomorium (Lampromyrmex) vaguum Santschi, 1930a: 68, figs 26-29. Syntype workers, female, Zaire: 
Leopoldville, vi.1918 (G. Maes) (NMB) [examined]. 

Worker. TL 1-3-1-4, HL 0-37-0-40, HW 0-30-0-31, CI 76-82, SL 0-24-0-26, SI 80-86, PW 0-18-0-20, 
AL 0-36-0-42 (10 measured). 

Clypeal carinae moderately developed but distinct, widely separated and divergent anteriorly. Median 
portion of clypeus shallowly prominent and unarmed, its anterior margin more or less transverse between 
the apices of the clypeal carinae. Maximum diameter of eye 0-20-0-23 x HW. In profile the eye 
conspicuously longer than high and consisting of an outer ring of ommatidia enclosing a single longitudinal 
row of 2-3 ommatidia. Sometimes one or two other ommatidia may also be enclosed in the ring, but this is 
rare. In full-face view the eyes distinctly in front of the midlength of the sides. Antennae 11-segmented. 
Scapes, when laid straight back from their insertions, failing to reach the occipital margins. Promesonotum 
in profile more or less flat posteriorly, sloping to the narrow but impressed metanotal groove. Propodeum 
in profile with dorsum and declivity forming a single smooth broad curve. Petiole node low and subconical, 
narrowly rounded above. Subpetiolar process a narrow inconspicuous strip below the short anterior 
peduncle. Postpetiole smaller than petiole in profile, lower and much more broadly rounded. All dorsal 
surfaces of head and body with standing hairs, the promesonotum characteristically with a distinct clump of 
5-6 (rarely 4) pairs of standing hairs on the anterior half of the pronotum and more sparsely distributed 
pairs of hairs behind this. Sculpture absent except for metanotal cross-ribs and sometimes with faint 
shagreening on the mesopleuron. Colour ranging from dull yellow to medium brown. 

I am treating all the samples mentioned below as a single species, vaguum, based on the combination of 
characters noted above and those in the key. It is fairly certain that more than one sibling species is involved 
here, but the few short series presently available for study do not permit any objective subdivision of the 
mass at this time. 



SOLENOPSIS GENUS-GROUP 419 

Among the Afrotropical species with 11 antennal segments vaguum is presently characterised by its 
possession of a conspicuous clump of standing hairs on the anterior half of the pronotum, an area where the 
pilosity is obviously much denser than anywhere else on the dorsal alitrunk. 

Material examined 

Nigeria: Gambari (B. Bolton). Zaire: Kinshasa (Leopoldville) (G. Maes). Kenya: Galole, Hola 
(V. Mahnert & J.-L. Perret). Botswana: Maxwee (A. Russell-Smith). South Africa: Transvaal, Nelspruit 
(M. Sam ways) . 

Monomorium vecte sp. n. 

(Fig. 68) 

Holotype worker. TL 2- 1, HL 0-51 , HW 0-42, CI 82, SL 0-42, SI 100, PW 0-28, AL 0-58. 

Clypeal carinae sharply developed, close together posteriorly and subparallel for most of their length, 
weakly divergent anteriorly. Clypeus between the carinae transversely concave and the anterior clypeal 
margin between the carina! apices shallowly concave. Lateral and anterior margins of prominent median 
portion of clypeus meeting in blunt angles, without projecting denticles or corners. Maximum diameter of 
eye 0-21 x HW, with 5 ommatidia in the longest row. With the head in full-face view the posterior margins 
of the eyes just in front of the midlength of the sides of the head. Antennal scapes, when laid straight back 
from their insertions, reaching or fractionally surpassing the occipital margin. Sides of head behind eyes 
feebly convex and somewhat convergent posteriorly in full-face view, the occipital margin exceptionally 
shallowly concave medially, almost transverse. Head in profile shallowly biconvex, not dorsoventrally 
flattened. Promesonotal dorsum in profile evenly shallowly convex, the posteriormost portion of the 
mesonotum suddenly downcurved and much more steeply sloping to the very broad shallowly impressed 
metanotal groove, the latter traversed by long, strong cross-ribs. Propodeal dorsum shallowly convex in 
profile and sloping posteriorly, the dorsum rounding broadly and evenly into the declivity. Propodeal 
spiracle large and conspicuous. Petiole node in profile relatively low and broad, bluntly subconical and with 
both faces very feebly convex. Subpetiolar process a narrow laminar strip. Postpetiole in profile smaller 
than petiole, lower and more broadly rounded. All dorsal surfaces of head and body with standing hairs 
present, the promesonotum with 8 or more pairs. Sides of head behind eyes and leading edges of scapes 
with freely projecting fine hairs. Head and body mostly unsculptured and smooth except for minute 
hair-pits, but the metanotum strongly cross-ribbed and the mesopleuron with transverse fine rugulose 
sculpture on a feebly reticulate background. A few even weaker rugulae occur on the metapleuron below 
the large propodeal spiracle. Head and body entirely yellow except for a darker band apically on the first 
gastral tergite. 

Paratype workers. TL 2-0-2-4, HL 0-48-0-60, HW 0-38-0-48, CI 78-82, SL 0-39-0-48, SI 100-105, PW 
0-23-0-32, AK 0-52-0-68 (12 measured). 

As holotype but maximum diameter of eye 0-21-0-23 X HW and with 5-7 ommatidia in the longest row. 
The mesopleural sculpture is variable. In some paratypes there is only reticulation, without trace of 
overlying rugulae. The paratypes show distinct size-variation but this does not affect the diagnosis of the 
species. 

Holotype worker, Zimbabwe: Umtali, Melsetter, 1700 m, ii. 1969 {R. Mussard) (MHN). 
Paratypes. 12 workers with same data as holotype (MHN; BMNH; MCZ). 
Non-paratypic material examined. Rwanda: Kayove, 2100 m, 23. iv. 1973 (P. Werner). 

The non-paratypic material consists of a short series whose size is at the lower end of the type-series' 
range. They agree very well with the holotype but tend to have the subpetiolar process smaller and the 
clypeal carinae slightly more strongly divergent anteriorly. 

M. vecte is close to firmum within the scW/zd-complex. Both species have relatively dense pilosity, 
broad shallow metanotal groove with strong cross-ribs and relatively large propodeal spiracle. The two are 
separated by size, firmum averaging larger, and by the presence of projecting pilosity on the sides of the 
head behind the eyes in vecte. Apart from these characters vecte has conspicuous mesopleural sculpture 
and a relatively small subpetiolar process. Infirmum the mesopleuron is smooth to very faintly sculptured, 
and the subpetiolar process is usually distinctly larger. Compare Figs 67, 68. 



420 B. BOLTON 

Monomorium vonatu sp. n. 

Holotype worker. TL 20, HL 0-49, HW 0-41 , CI 84, SL 0-34, SI 83, PW 0-26, AL 0-54. 

Clypeal carinae sharp and conspicuous, widely divergent anteriorly and the triangular area enclosed by 
the carinae and anterior margin flat transversely. Clypeal carinae reachng the anterior margin on a pair of 
low but distinctly projecting broad denticles. Anterior margin between the denticles transverse. Maximum 
diameter of eye 0-24 x HW and with 6-7 ommatidia in the longest row. In full-face view the eyes in front of 
the midlength of the sides, though their posterior margins are close to the midlength. Antennal scapes, 
when laid straight back from their insertions, failing to reach the occipital margin. Alitrunk in profile with 
basically the same dorsal outline shape as fugelanum (Fig. 88). Promesonotum evenly convex, sloping 
posteriorly to the narrow but conspicuously impressed metanotal groove. Metanotal cross-ribs short but 
strongly developed and conspicuous. Propodeal spiracle minute and pinhole-like. Propodeal dorsum 
sloping downwards posteriorly, the dorsum and declivity rounding evenly together, not distinctly separ- 
ated, though the latter slopes more steeply than the former. Petiole in profile with a high narrow node 
which tapers to a point apically. The anterior and posterior faces meet in a sharp rim or edge which is 
continuous round the dorsum and sides of the node. Subpetiolar process an elongate but low lobe which 
runs to the level of the spiracle, anterior peduncle of petiole short and narrow. Postpetiole high and 
narrow, with a high and near-vertical anterior face; as on the petiole, the anterior and posterior faces meet 
in a sharp rim or edge. Standing hairs present on all dorsal surfaces of head and body, the promesonotum 
with 3 pairs. Sculpture absent except for minute hair-pits and metanotal cross-ribs. Colour glossy black. 

Holotype worker, Ghana: Mampong, 10. ii. 1970 (P. Room) (BMNH). 

This glossy black West African member of the altinode-comp\ex is immediately diagnosed by the 
structure of the petiole and postpetiole, which is shared only with the Kenyan mirandum. The only other 
West African member of this complex which is known, occidental, is also darkly coloured but, apart from 
lacking the petiolar configuration of vonatu, has a pair of elongate narrow teeth on the clypeus and a very 
large propodeal spiracle. M. mirandum, the closest known relative of vonatu, is spectacularly coloured 
black and yellow and has much longer antennal scapes (SI 97-100). 

The fossulatum-group 

(Figs 93-95) 

Worker. Monomorphic, with some size variation but without allometric variation. Mandibles unsculp- 
tured except for hair-pits, armed with 4 teeth which decrease in size from apex to base and which usually 
have the masticatory margin markedly oblique. Palp formula 2,2 (all species). Anterior clypeal margin 
without a pair of projecting teeth. Median portion of clypeus narrow and sharply raised, weakly bicarinate 
at least posteriorly, the carinae tending to fade out anteriorly. Median portion of clypeus very narrow 
posteriorly, distinctly narrower than the maximum width of either frontal lobe where it passes between 
them; frontal lobes and antennal insertions consequently very close together (Fig. 93). Eyes minute and 
point-like, of only one or two ommatidia and situated at the midlength of the sides; maximum diameter of 
eye only 0-05-0-08 x HW. Antennae with 12 segments terminating in a large club of 3 segments. Head 
relatively narrow and scapes of moderate length, CI 72-85, SI 90-110. Cephalic dorsum unsculptured 
except for hair-pits. Lateral portions of clypeus and area immediately behind them, and area around 
antennal fossae, without striolate or costulate sculpture. Propodeum without transverse sculpture dorsally, 
with the spiracle circular to subcircular; propodeal dorsum meeting declivity in an obtuse angle or weakly 
denticulate at the junction. Petiole with a long anterior peduncle, the petiolar spiracle at the node or 
immediately in front of the anterior face of the node when viewed in profile . Fine standing hairs present on 
all dorsal surfaces of head and body except for the propodeum, where they are usually sparse or absent. 
(Workers examined: all included in this study plus the extralimital species fossulatum and talpa.) 

Female. Diagnosis as worker but females considerably larger than conspecific workers and with much 
larger eyes. Ocelli present and alitrunk with full complement of flight sclerites. HW approximately equal to 
the maximum width of the mesoscutum, the latter extensive and slightly longer than broad, with parapsidal 
grooves absent or at most extremely faint. Pronotum not forming part of dorsal alitrunk; in dorsal view 
only the extreme anterolateral corners of the pronotum can be seen. Axillae large, triangular in dorsal view 
and the distance separating them is much less than the length of either axillary sclerite. Forewing with 
cross-vein m-cu present (cryptobium). (Females examined: cryptobium, malamixtum, sersalatum, talpa.) 



SOLENOPSIS GENUS-GROUP 421 

Male. Unknown. 

This small species-group, one of the most conspicuous in the genus, contains seven Afrotropical and two 
extralimital species. The previously described Afrotropical species were formerly referred to the genus 
Syllophopsis, now synonymized (p. 297), whilst the extralimital species have always been retained in 
Monomorium. The Afrotropical species are very widely distributed within the region. All are minute and 
constitute a minor fraction of the extensive leaf litter and topsoil fauna of the region. The extralimital 
species are widespread in the Indo- Australian region and on the islands of the Pacific and Indian Oceans 
(Wilson & Taylor, 1967). Much of their island spread may be the result of tramping behaviour in the 
relatively recent past. 

These extralimital forms, fossulatum and talpa, apparently do not occur in the Afrotropical region, at 
least I have seen no African material referable to the two. In fossulatum the entire mesopleuron is 
sculptured, a feature not seen in Afrotropical species, and in talpa the promesonotum is much more 
strongly dome-shaped than in any species of sub-Saharan Africa. 

Workers of the fossulatum-group resemble those of the hanneli-group in many of their diagnostic 
features, but this similarity is certainly the result of convergence as other characters such as the 
construction of the clypeus and petiole are markedly different, compare Figs 93, 94,97, 98. Females of the 
two groups show little similarity. Those of the fossulatum-group have an alitrunk structure usual for 
Monomorium whilst those of the hanneli-group show an alitrunk structure which is derived from this plan. 
The real origins of the fossulatum-group appear to lie within the monomorium-group, being derived from 
them in the worker caste by reduction of the eyes, approximation of the antennal insertions (thus reducing 
the width of the clypeus between the frontal lobes and narrowing the raised median portion of the clypeus) , 
enlargement of the antennal club, and lengthening of the petiolar anterior peduncle. An apparently 
undescribed species from Madagascar (in BMNH) shows some character states intermediate between the 
monomorium-group and the fossulatum-group. Its eyes are small (about 7 ommatidia), the antennal 
insertions are not so closely approximated as in \he fossulatum-group, and the petiolar peduncle, though 
longer than is usual in the monomorium-group, is not as long as that seen in fossulatum and its allies. 

Monomorium cryptobium (Santschi) comb. n. 

Syllophopsis cryptobia Santschi, 1921b: 119, figs 2a-c. Holotype worker, Zaire (Le Moult) (NMB) 
[examined]. 

Worker. TL 1-3-1-7, HL 0-36-0-43, HW 0-28-0-34, CI 78-83, SL 0-27-0-34, SI 93-100, PW 0-20-0-26, 
AL 0-40-0-50 (15 measured). 

Minute species with eyes of a single ommatidium, the maximum diameter of the eye 0-06 x HW or less. 
Promesonotum in profile with its dorsal outline evenly convex but rather shallowly so, not strongly 
dome-shaped. Metanotal groove narrow in profile but sharply impressed, the propodeal dorsum behind 
the groove sloping posteriorly. Highest point of propodeum immediately behind the metanotal groove, 
without a sharp central peak or narrow transverse crest. Junction of propodeal dorsum and declivity 
equipped with a pair of minute tubercles or tiny denticles. All dorsal surfaces of head and body with 
numerous short erect to suberect hairs and erect to suberect pubescence. Hairs on the propodeum sparser 
than elsewhere on the alitrunk, reduced to one or two pairs. In full-face view the antennal scapes and sides 
of the head behind the eyes with erect to subdecumbent pubescence; pubescence not appressed every- 
where. Head and body smooth and shining everywhere except for scattered minute hair-pits. Sides of 
alitrunk smooth except for the impressed groove where mesopleuron meets metapleuron, and the area of 
the bulla of the metapleural gland. Colour usually dull yellow to light brownish yellow but a few samples 
darker, medium brown. 

Widely distributed in the leaf litter and topsoil layer of the west and central African forests, this minute 
species is the commonest member of the group. As noted above the colour of cryptobium is usually dull 
yellow to light brownish yellow, but a few individuals from Cameroun are considerably darker. At present I 
cannot assess the significance of this and so retain the darker colour samples in cryptobium. 

The closest relative of cryptobium is malamixtum; for discussion see under the latter name. 

Material examined 

Ivory Coast: Dropleu (Mahnert & Perret);lssoneu (Mahnert & Perret);Man (Mahnert & Perret). Ghana: 
Mampong (P. Room); Mampong (£>. Leston); Tafo (B. Bolton); Axim (C. A. Collingwood) . Nigeria: 



422 B. BOLTON 

Ibadan (A. Russel-Smith) . Cameroun: Nkoemvon (D. Jackson). Gabon: He aux Singes (/. A. Band). 
Zaire: no loc. (Le Moult). 

Monomorium elgonense (Santschi) comb. n. 

Syllophopsis elgonensis Santschi, 19356: 267, fig. 4. Holotype worker, Kenya: Mt Elgon, camp 1, st. 13, 
2100 m, 1932-33 (Jeannel & Chappuis) (MNHN) [examined]. 

Worker. TL 1-9-2-0, HL 0-48-0-51, HW 0-40-0-43, CI 80-84, SL 0-36-0-39, SI 90-95, PW 0-29-0-30, 
AL 0-56-0-60 (8 measured). 

Eyes of a single ommatidium, maximum diameter 0-05-0-07 x HW. Antennal scapes relatively short, 
SI < 100. Promesonotal dorsal outline evenly rounded in profile, the metanotal groove conspicuously 
impressed. In profile the propodeal dorsum immediately behind the groove with a small peak, which 
appears as a weak transverse crest in dorsal view. Propodeal dorsum behind this peak sloping posteriorly to 
the pair of short broad denticles or prominent triangular angles which mark the junction of dorsum and 
declivity. All dorsal surfaces of head and body with numerous short hairs and very sparse pubescence. 
Propodeum with only 1-2 pairs of hairs. Pubescence on sides of head behind eyes decumbent to appressed, 
that on the antennal scapes more elevated but not erect. Unsculptured everywhere except for scattered 
minute hair-pits, and some faint striation on the bullae of the metapleural glands; lower halves of 
mesopleuron smooth and shining. Colour uniform yellow. 

The holotype is much abraded and densely coated with old glue which obscures the pilosity and some of 
the surface detail. Despite this it matches the other Kenyan series noted below, which I am certain is 
conspecific with the holotype. 

M. elgonense is separated from jonesi and thrascoleptum by its shorter scapes, from the Rwandan 
sersalatum and the west African malamixtum by its smooth mesopleuron, from modestum by its deeply 
impressed metanotal groove, and from cryptobium by being larger and having the propodeum produced 
into an acute peak behind the metanotal groove. At present elgonense is known only from Kenya. 

Material examined 
Kenya: Mt Elgon {Jeannel & Chappuis); Embu, Kirimiri Forest west of Runyenje (Mahnert & Ferret). 

Monomorium jonesi Arnold 

Syllopsis [sic] arnoldi Santschi, 19216: 120, figs 2d,e. Syntype workers, South Africa: Natal, Mfongosi 

(Jones) (NMB) [examined]. [Junior secondary homonym of Monomorium arnoldi Forel, 19136: 137.] 
Monomorium (Syllophopsis) jonesi Arnold, 1952: 465. [Replacement name.] 

Note. The published original description of this species was under the name arnoldi, as noted above, but 
the determination label on the syntypes gives arnodiella [sic]. Arnold (1952: 465-466) criticized the 
genus-level status of Syllophopsis which it held at that time, and reduced it to a subgenus of Monomorium, 
erecting jonesi as a replacement name for the secondary homonym with arnoldi thus produced. Ettershank 
(1966) maintained Syllophopsis as a valid genus, without, however, having seen any material referable to 
the group, and thus treated jonesi as an unnecessary replacement name. With the present confirmation of 
Syllophopsis as a junior synonym of Monomorium the rules of homonymy again come into effect, and 
jonesi is reinstated as the valid name for this species. 

Worker. TL 2-2-2-3, HL 0-54-0-55, HW 0-40-0-41, CI 72-75, SL 0-43-0-44, SI 107-110, PW 0-29-0-30, 
AL 0-60-0-64 (2 measured). 

Eyes of a single ommatidium, maximum diameter 0-05 x HW. Head relatively narrow (CI 75 or less) 
and antennal scapes relatively long, with SL always greater than HW (SI > 100). Promesonotal outline in 
profile evenly domed-convex, the metanotal groove sharply but narrowly impressed. Propodeal dorsal 
outline rising from the metanotal groove, then curving into the dorsum proper and sloping to the minute 
triangular denticles at the junction of dorsum and declivity; without a raised peak or transverse ridge at the 
highest point immediately behind the metanotal groove. All dorsal surfaces of the head and body with 
numerous short standing hairs. These hairs not as numerous as elsewhere in the group but I suspect that the 
syntypes are somewhat abraded. Scapes, tibiae and sides of head behind eyes, when seen in full-face view, 
with sparse appressed pubescence, none of which is erect or suberect. Head unsculptured except for 
minute scattered hair-pits. Alitrunk unsculptured except for the oblique impressed area between the 



SOLENOPSIS GENUS-GROUP 423 

mesopleuron and metapleuron/propodeum where some faint ribbing is present; and on the metapleuron 
which has some feeble longitudinal rugulae. Propodeum unsculptured above. Colour uniform yellow. 

This quite distinctive member of the group is known only from the two syntypes which constitute the 
type-series. M. jonesi appears to be closest related to thrascoleptum from Ivory Coast, but jonesi lacks the 
dense erect to suberect pubescence which is so obvious in thrascoleptum. 

Material examined 
South Africa: Natal, Mfongosi (Jones). 

Monomorium malamixtum sp. n. 

Holotype worker. TL 20, HL 0-44, HW 0-36, CI 82, SL 0-36, SI 100, PW 0-27, AL 0-54. 

Minute species with eyes of a single ommatidium, the maximum diameter 0-06 x HW. With head in 
full-face view the sides and the occipital margin very shallowly convex. Antennal scapes of moderate 
length, SI 100 (range of SI 91-100 in all samples). With alitrunk in profile the promesonotal dorsum evenly 
arched-convex, the metanotal groove deeply and conspicuously impressed. Propodeal dorsum immedi- 
ately behind metanotal groove rising to a narrow acute peak, behind which the surface slopes posteriorly to 
the minute propodeal denticles. In dorsal view the propodeal peak is seen as a narrow inconspicuous 
transverse crest immediately behind the metanotal groove. Dorsal surfaces of head and body with fine hairs 
and pubescence, sparsest on the propodeum where only a couple of pairs of hairs occur. With the head in 
full-face view the scapes and sides behind the eyes with subdecumbent to decumbent pubescence, no 
pubescence conspicuously erect. All dorsal surfaces of head and body unsculptured except for scattered 
minute hair-pits but the sides of the alitrunk with the lower two-thirds of the mesopleuron finely 
punctulate-shagreenate, the impression between mesopleuron and propodeum very finely cross-ribbed 
and the metapleural gland bullae finely striolate. Colour brown. 

Paratype workers. TL 1-6-2-0, HL 0-40-0-44, HW 0-32-0-37, CI 80-85, SL 0-32-0-36, SI 91-100, PW 
0-24-0-27, AL 0-44-0-54 (10 measured). As holotype but maximum diameter of eye 0-06-0-08 x HW. 
Mesopleural sculpture covers the lower one-half to two-thirds of the sclerite. 

Holotype worker, Ivory Coast: Man, Mt Tonkoui, 900 m, 13.x. 1980 (Mahnert & Perret) (MHN). 

Paratypes. 15 workers and 2 females with same data as holotype; 12 workers, Tai Forest, 17.x. 1980 
{Mahnert & Perret) (MHN; BMNH; MCZ). 

Non-paratypic material examined. Ivory Coast: Agboville, Yapo Forest, Yapo-Gare (/. Lobt); Abidjan, 
Banco Nat. Pk. (/. Lobl); Dropleu (Mahnert & Perret). Togo: Palime, Klouto Forest (Vit). 

The non-paratypic material matches the type-series except that the Togo specimens are lighter in colour 
than those from Ivory Coast, being yellowish brown. The workers in this short series may be tenerals. 

M. malamixtum resembles the widespread cryptobium but the two are usually separable on colour alone, 
the former being brown and the latter yellow. However, the presence of relatively dark individuals of 
cryptobium in Cameroun and possibly of light individuals in Togo means that colour alone is not always 
diagnostic. Separation of such dubious samples (as well as of more normally coloured material) rests on the 
fact that in cryptobium the mesopleuron is smooth and the propodeum does not have an acute peak behind 
the metanotal groove , whilst in malamixtum at least the lower half of the mesopleuron is sculptured and the 
metanotal groove is followed by an acute peak on the propodeum which appears as a narrow transverse 
crest in dorsal view. 

Monomorium modestum Santschi 
(Fig. 95) 

Monomorium modestum Santschi, 19146: 17. Syntype workers, South Africa: Natal, Stamford Hill, 

i.1905 (/. Tragardh) (NMB) [examined]. 
Monomorium (Syllophopsis) modestum Santschi; Santschi, 1915: 260. 
Monomorium (Syllophopsis) modestum var. boerorum Santschi, 1915: 260, fig. 9. Syntype workers, South 

Africa: Pretoria (NMB) [examined]. [Junior primary homonym of Monomorium minutum var. 

boerorum Forel, 1910a: 442.] Syn. n. 
Monomorium (Syllophopsis) modestumvar. transwaalensis Emery , 1922: 175. [First replacement name for 

boerorum Santschi.] Syn. n. 



424 B. BOLTON 

Monomorium (Syllophopsis) modestum var. smutsi Wheeler, 1922: 867. [Second replacement name for 
boerorum Santschi.] Syn. n. 

Worker. TL 1-7-2-0, HL 0-39-0-48, HW 0-32-0-36, CI 74-82, SL 0-29-0-34, SI 94-100, PW 0-22-0-26, 

AL 0-44-0-52 (15 measured). 

Within the limits given for the fossulatum-group (see above) modestum is presently diagnosed by its 
yellow colour, rounded to angular propodeum which lacks denticles at the junction of dorsum and declivity 
seen in all other species of the group, and by its lack in profile of a sharply impressed U- or V-shaped 
metanotal groove, modestum having instead a simple indentation of the surface which is scarcely or not 
impressed (Fig. 95). 

This overall diagnosis applies to the three widely separated populations cited in the material examined. 
Very little material of each is available for study and I suspect strongly that these populations may 
represent more than one species. However, until more collections of forms fitting the above definition have 
been acquired, no meaningful statements regarding their species-level taxonomy can be made. 

Material examined 

Ivory Coast: Man (Mahnert & Ferret); Adiopodoume For. Biol. Res. (/. Lobt). Kenya: Tana Riv., 
Galole (Hola) {Mahnert & Perret). South Africa: Natal, Stamford Hill (/. Trdgardh); St Lucia Estuary (D. 
J. Brothers); Pretoria; Cape Prov., Grahamstown (W. L. Brown). 

Monomorium sersalatum sp. n. 

Holotype worker. TL 2-2, HL 0-52, HW 0-42, CI 81, SL 0-42, SI 100, PW 0-31 , AL 0-62. 

Eyes of a single ommatidium, maximum diameter 0-07 x HW. Antennal scapes of moderate length, SI 
100 in holotype (SI 94-100 in paratypes). Promesonotum in profile with dorsal outline evenly convex, the 
metanotal groove a sharply defined V-shaped impression. Propodeum immediately behind the metanotal 
groove rising to an acute peak then sloping quite steeply posteriorly to a pair of weakly projecting 
denticuliform angles which separate dorsum from declivity. All dorsal surfaces of head and body with 
numerous short standing hairs except for the propodeum where only two pairs are present. With the head 
in full-face view the scapes and sides of the head behind the eyes with erect to suberect pubescence . Femora 
and tibiae with conspicuously elevated pubescence. Dorsal surfaces of head, alitrunk and gaster unsculp- 
tured except for scattered minute hair-pits. Sides of pronotum smooth. Lower half of mesopleuron finely 
but conspicuously punctulate-shagreenate, the upper half of the mesopleuron retaining vestiges of similar 
sculpture. Impression between mesopleuron and metapleuron/propodeum finely cross-ribbed. Sides of 
propodeum unsculptured but metapleuron finely longitudinally striate. Colour uniform yellow. 

Paratype workers. TL 2-0-2-2, HL 0-47-0-52, HW 0-38-0-44, CI 80-85, SL 0-36-0-42, SI 94-100, PW 
0-26-0-31, AL 0-50-0-62 (13 measured). As holotype. 

Holotype worker, Rwanda: Kamiranzovu, 1900 m, i.1976 (P. Werner) (MHN). 

Paratypes. 5 workers with same data as holotype; 6 workers, Kayove, 2100 m, 25. v. 1973 (P. Werner); 
3 workers and 1 female, Rangiro, 1800 m, 10.vii.1973 (P. Werner); 10 workers, Rangiro, ix.1976 
(P. Werner) (MHN; BMNH; MCZ). 

Known only from Rwanda, this montane species possesses a distinctly sculptured lower mesopleuron, a 
feature encountered in the African species of this group only here and in the west African malamixtum. 
The latter species, however, averages smaller than sersalatum and is much darker in colour. 

Monomorium thrascoleptum sp. n. 

(Figs 93, 94) 

Holotype worker. TL2-1, HLO-49, HW0-40, CI 81, SL0-41, SI 103, PWO-30, ALO-58. 

Eyes of a single ommatidium, maximum diameter 0-07 x HW. Antennal scapes relatively long 
(SI > 100). Promesonotum in profile evenly rounded, the metanotal groove deeply and conspicuously 
impressed. Propodeal dorsum immediately behind the metanotal groove raised and angular in profile, but 
not surmounted by an acute peak which appears as a transverse crest in dorsal view. Behind this highest 
point the propodeal dorsum sloping shallowly to the angular to slightly prominent corners which separate 
dorsum and declivity. All dorsal surfaces of head and body with fine standing hairs, sparsest on the 



SOLENOPSIS GENUS-GROUP 425 

propodeum and densest on the head and gaster. With the head in full-face view the sides behind the eyes 
and the antennal scapes with conspicuously elevated pubescence which is suberect to subdecumbent. 
Entire body smooth and shining, unsculptured except for hair-pits, cross-ribbing at the 
mesopleural-propodeal junction and a few faint striae over the bulla of the metapleural glands. Colour 
uniform clear yellow. 

Paratype workers. TL 1-9-2-2, HL 0-46-0-50, HW 0-38-0-41 , CI 80-83, SL 0-40-0-44, SI 103-110, PW 
0-28-0-31 , AL 0-56-0-60 (8 measured). As holotype but some with the angulate corners of the propodeum 
more strongly prominent. 

Holotype worker, Ivory Coast: Nzi Noua, 13. i. 1977 (W. L. Brown) (MCZ). 
Paratypes. 8 workers with same data as holotype (MCZ; BMNH). 

M. thrascoleptum is the largest member of this group found in West Africa, and the only West African 
species with SI consistently greater than 100. Apart from this thrascoleptum differs from modestum by 
having the metanotal groove deeply impressed, and from malamixtum by being yellow and lacking 
mesopleural sculpture. 

The haime/i-group 

(Figs 96-98) 

Worker. Monomorphic. Mandibles unsculptured, with 4 teeth which decrease in size from apex to base. 
Palp formula 2,2 (Jacksoni, hanneli, invidium). Median portion of clypeus with a pair of sharply defined 
posteriorly convergent raised carinae, which terminate at the anterior margin in a pair of short teeth. 
Frontal lobes close together, the median strip of clypeus which runs between them narrow, narrower to 
only fractionally wider than either of the frontal lobes. Eyes small, the maximum diameter 0-13-0-18 x 
HW; the eyes always with more than 5 ommatidia in total but less than 25 , situated in front of the midlength 
of the sides of the head. Antennae with 12 segments, terminating in a large 3-segmented club. Head 
moderately broad and scapes relatively short, CI 81-90, SI 75-86. Propodeum usually very finely 
transversely sculptured, sometimes smooth, bluntly angular to bluntly bidentate where the dorsum meets 
the declivity. Petiolar peduncle short in profile, the node high and the spiracle behind the level of the 
anterior face of the node. Cephalic dorsum unsculptured except for hair-pits; lateral portions of clypeus, 
area immediately behind lateral portions of clypeus and area around antennal fossae without striolate or 
fine costulate sculpture. Fine standing hairs present on all dorsal surfaces of head and body. (Workers 
examined: all species of the group.) 

Female. Only very slightly larger than the conspecific worker. As worker but with proportionately much 
larger eyes, ocelli present, and alitrunk with a full complement of flight sclerites. HW distinctly greater 
than the maximum width of the mesoscutum, the latter as broad as long or slightly broader than long. In 
dorsal view the pronotum forming a part of the dorsal alitrunk, appearing as a broad transverse collar in 
front of the mesoscutum and being much wider laterally than mesally. Parapsidal grooves conspicuous to 
vestigial. Axillae in dorsal view wedge-like and with a gap between their inner apices; the length of the gap 
about equal to the length of one of the axillary sclerites. Propodeum bluntly angular to low bidentate at 
junction of dorsum and declivity. (Females examined: jacksoni, invidium.) 

Male. Unknown. 

The five species of this distinctive and purely Afrotropical group are all very closely related and have no 
obviously related forms outside the region. With their narrow median clypeus, closely approximated 
frontal lobes and small eyes they appear at first glance to be close to thefossulatum-group, but in workers of 
that group the petiolar peduncle is long and the node low, the eyes are usually only of a single ommatidium 
and the clypeus lacks teeth anteromedially. In the females the pronotum does not form part of the dorsal 
alitrunk in the fossulatum-group and the axillae of the latter are much closer together. It thus appears that 
the characters apparently shared by the workers are the result of convergence rather than indicators of 
genuine relationship. 

All species of the hanneli-group form part of the leaf litter and topsoil fauna , nesting in rotten twigs in the 
litter layer or in tree stumps. Of the three West African species one, invidium, is very widespread and 
ranges from Ivory Coast to Cameroun in the forest zone. The other two, guineense and jacksoni, are only 
known from the forests of Guinea and Cameroun respectively. The females of invidium and jacksoni 



426 B. BOLTON 

mentioned above were the reproductives of established colonies; alate females remain unknown, as do all 
males of this group. The two Kenyan species, hanneli and valtinum, are only known from the workers and 
from relatively few series. 

Monomorium guineense (Bernard) 

(Fig. 96) 

Epixenus guineensis Bernard, 1952: 238, figs 10F-I. Syntype workers, Guinea: Mont To, ravin l,st. B2.41, 

foret, 21.2 (Lamotte) (MNHN) [examined]. 
Monomorium guineense (Bernard) Brown & Wilson, 1957: 245. 

Worker. TL 2-3, HL 0-56, HW 0-48, CI 86, SL 0-38-0-39, SI 79-81, PW 0-35-0-36, AL 0-62 
(2 measured). 

As the more common and more widely distributed invidium but with smaller eyes, the maximum 
diameter 0-13 x HW and with 4 ommatidia in the longest row. The head and alitrunk are unsculptured 
everywhere except for faint hair-pits, and the propodeal dorsum lacks the faint transverse rugulae usually 
seen in invidium. In profile the propodeal dorsum meets the declivity in a pair of prominent but obtuse 
angles and the body colour is uniform dark brown. The nodes of the petiole and postpetiole are much more 
strongly antero-posteriorly compressed and scale-like than in any other member of the group (Fig. 96), the 
nodes in profile being high narrow and very narrowly rounded dorsally . The postpetiole is slightly narrower 
than the petiole in profile. In dorsal view both nodes are broad, the dorsal surfaces very short from front to 
back and the postpetiole only fractionally thicker than the petiole. 

Known only from the few syntype workers constituting the type-series guineense is separated from 
invidium by the characters noted above. The third West African species of this group, jacksoni, is quickly 
separated from guineense as the former has the propodeum very strongly sculptured, as well as having 
petiole and postpetiole nodes which are broader than in guineense. 

Because of its relatively broad and narrow nodes guineense was first described in Epixenus, a spurious 
generic name which covered a loose assemblage of salomonis-group species linked by their development of 
apterous or ergatoid females and a tendency in some of their females to possess relatively broad narrow 
nodes. This was obviously the criterion uppermost in Bernard's mind when he assigned guineense to 
Epixenus, but it is now plain that guineense is not closely related to any salomonis-group species and the 
name Epixenus itself is a straight synonym of Monomorium. 

Monomorium hanneli Forel 

Monomorium hanneli Forel, 1907a: 18. Holotype worker, Kenya: Mto-ya-Kifaru (Katona) (MNH) 

[examined]. 
Monomorium moestum Santschi, 1914a: 74, fig. 7. Holotype worker, Kenya: Naivasha, 1900 m, st. no. 14, 

i.xii.1911 (Alluaud & Jeannel) (NMB) [examined]. Syn. n. 

Worker. TL 2-4-2-8, HL 0-54-0-64, HW 0-45-0-56, CI 83-90, SL 0-34-0-44, SI 75-81, PW 0-30-0-40, 
AL 0-60-0-76 (18 measured). 

Mandibles smooth and shining, with scattered hair-pits. Clypeal carinae very sharply defined and 
terminating in a pair of short but acute triangular teeth. Eyes small, maximum diameter 0-16-0-19 x HW 
and with 4-6 ommatidia in the longest row. Eyes with 11-21 ommatidia in all, arranged in a peripheral ring 
which encloses 2-7 ommatidia. Promesonotum evenly but shallowly convex in profile, the metanotal 
groove impressed and the propodeal dorsum behind the groove sloping posteriorly. Dorsal surface of 
propodeum meeting the declivity in a blunt obtuse angle. Lateral margins of propodeal dorsum with low 
blunt marginations, very low and rounded in larger workers. Dorsal sculpture of propodeum terminates at 
the marginations and helps to define their positions. Dorsum between propodeal marginations transversely 
flat anteriorly, extremely shallowly concave posteriorly. Petiole node in profile high and narrow, the height 
of the node from spiracle to apex distinctly greater than the distance from the spiracle to the insertion of the 
peduncle. In dorsal view both nodes transverse, distinctly very much broader than long. Cephalic dorsum 
unsculptured except for small hair-pits and a few short rugulae behind the frontal lobes. Promesonotum 
glassy smooth dorsally but propodeal dorsum with superficial fine transverse costulae which are faint or 
almost effaced medially in some individuals. Sides of alitrunk smooth except for some fine longitudinal 
rugulae on the metapleuron. Petiole, postpetiole and gaster unsculptured. All dorsal surfaces of head and 
body with conspicuous standing hairs. Colour glossy brown, the appendages lighter. 



SOLENOPSIS GENUS-GROUP 427 

This is a larger and more size-variable relative of valtinum, the only other East African species in this 
group. The eyes oihanneli are larger than those of valtinum, both relatively and absolutely. 

Material examined 

Kenya: Mto-ya- Kifaru (Katona); Narok, Loita Hills, Morijo (Mahnert & Perret); Taita Hills, nr 
Wundanyi (V. Mahnert); Naivasha (Alluaud & Jeannel). 

Monomorium invidium sp. n. 

(Figs 97, 98) 

Holotype worker. TL 1-9, HL 0-48, HW 0-41, CI 85, SL 0-34, SI 83, PW 0-31, AL 0-54. 

Mandibles smooth and shining, unsculptured except for scattered hair-pits. Pair of teeth on anterior 
clypeal margin conspicuous. Maximum diameter of eye 0T5 x HW, with 4 ommatidia in the longest row; 
the outer peripheral ring of ommatidia enclosing only two ommatidia within the ring. Promesonotum 
shallowly convex in profile, the metanotal groove narrow and shallowly impressed. Propodeal dorsum 
sloping downwards posteriorly and rounding narrowly into the declivity, the dorsal surface of the 
propodeum bluntly marginate laterally and the dorsum between the blunt margins very shallowly concave. 
Petiole and postpetiole in profile high and narrow, the nodes narrowly but bluntly rounded above and the 
latter node slightly thicker than the former. In dorsal view the nodes broadly transversely elliptical. 
Cephalic dorsum behind the frontal lobes smooth, unsculptured except for hair-pits. Sides of head without 
a narrow sculptured strip running from the anterior margin of the eye to the base of the mandible, and the 
occipital margin unsculptured. Promesonotum smooth and highly polished both dorsally and laterally. 
Remainder of sides of alitrunk with sculpture only on lower half and round the margin of the mesopleuron, 
on the metapleuron, and with a small sculptured patch on the propodeum behind the level of the spiracle. 
Propodeum in dorsal view finely and faintly transversely rugulose. Petiole postpetiole and gaster 
unsculptured in dorsal view. All dorsal surfaces of head and body with numerous standing hairs. Colour 
highly polished blackish brown. 

Paratype workers. TL 1-8-2-0, HL 0-48-0-50, HW 0-40-0-42, CI 82-85, SL 0-33-0-36, SI 81-86, PW 
0-30-0-31 , AL 0-54-0-56 (10 measured). As holotype but eyes may have 3-4 ommatidia in the longest row 
and have maximum diameter 0-15-0-17 x HW. Sculpture on propodeal dorsum is sometimes effaced 
medially, being visible only close to and on the lateral marginations. On the sides of the alitrunk the 
mesopleuron may be smooth with only peripheral sculpture developed, and the sculptured patch behind 
the propodeal spiracle is sometimes absent. Colour varies from blackish brown to jet black. 

Holotype worker, Nigeria: Ibadan, IITA, sample 06, 28. iv. 1981 (A. Russell-Smith) (BMNH). 

Paratypes. 10 workers and one dealate female with same data as holotype (BMNH; MHN; MCZ). 

Non-paratypic material examined. Guinea: Mt Nimba (Villiers). Ivory Coast: Sassandra (/. Lob!):, 
Abidjan, Banco Nat. Pk. (/. Lobl); Man (/. Lobl); Bingerville (Mahnert & Perret); Nzi Noua (W. L. 
Brown); Issoneu (Mahnert & Perret); Abidjan (T. Diomande). Ghana: Mampong (P. Room). Nigeria: 
Ile-Ife (/. T. Medler); Gambari (B. Bolton); Gambari (B. Taylor). Cameroun: Nkoemvon (D. Jackson). 

The non-paratypic material shows the following range of dimensions. TL 1-8-2-3, HL 0-46-0-56, HW 
0-39-0-48, CI 82-86, SL 0-32-0-38, SI 79-84, PW 0-30-0-34, AL 0-50-0-62 (15 measured). In these series 
eye size shows the range 0-14-0-17 x HW and the eyes have 3-5 ommatidia in the longest row. In larger 
workers the peripheral ring of ommatidia may surround 5 others, rather than the 2-3 which seems more 
usual. In some individuals the sculpture of the propodeal dorsum is almost or entirely effaced, leaving the 
surface glassy smooth. Similarly the sides of the alitrunk may lack sculpture except in the vicinity of the 
metapleural gland bulla. Outline shape of the propodeum in profile varies from narrowly but bluntly 
rounded to sharply obtusely angular. 

M. invidium is the commonest and most widely distributed member of this small group in West Africa. It 
separates easily from the other two known West African species asjacksoni, known only from Cameroun, 
is much more strongly sculptured, and guineense from Guinea has much narrower scale-like nodes. 

Monomorium jacksoni sp. n. 

Holotype worker. TL 2-0, HL 0-46, HW 0-39, CI 85, SL 0-32, SI 82, PW 0-29, AL 0-55. 

Mandibles unsculptured except for hair-pits. Median portion of clypeus flanked by a pair of short 
triangular denticles which are not strongly prominent, but the edges of the median clypeal bicarination 



428 B. BOLTON 

V-shaped and very sharply defined. Eyes small, maximum diameter 0-15 x HW and with only 3 ommatidia 
in the longest row. Eye consisting of only 6 ommatidia in total, without central ommatidia surrounded by a 
peripheral ring. Promesonotum shallowly convex, the metanotal groove weakly impressed. Propodeal 
dorsum behind the metanotal groove sloping posteriorly; dorsum and declivity separated by a blunt angle. 
Dorsum of propodeum marginate laterally, the marginations diverging posteriorly. Petiole and postpetiole 
shaped as in invidium (Fig. 98). Cephalic dorsum smooth, unsculptured except for hair-pits and some short 
faint costulae behind the frontal lobes. Sides of head mostly unsculptured but the strip of cuticle between 
the eye and the mandibular insertion sculptured, this sculptured strip being slightly wider than the eye 
itself. Promesonotum glassy smooth everywhere, mesopleuron sculptured except for a smooth patch 
posterodorsally. Metapleuron completely sculptured as is the propodeal side except for a smooth area 
around the spiracle. Propodeal dorsum conspicuously transversely rugulose, the spaces between the 
rugulae punctate. Petiole, postpetiole and gaster unsculptured in dorsal view. All dorsal surfaces of head 
and body with numerous standing hairs. Colour of head and body blackish brown. 

Paratype workers. TL 1-8-2-0, HL 0-44-0-47, HW 0-38-0-40, CI 85-89, SL 0-30-0-34, SI 79-85, PW 
0-27-0-30, AL 0-52-0-56 (12 measured). As holotype but eyes with maximum diameter 0-14-0-15 x HW 
and with 6-7 ommatidia in total. In some almost the upper third of the mesopleuron is unsculptured. 

Holotype worker, Cameroun: Nkoemvon, 12. i. 1980 (D. Jackson) (BMNH). 

Paratypes. 7 workers and 1 female with same data as holotype; 5 workers with same data but 5. i. 1980 
(BMNH;MHN;MCZ). 

Very closely related to invidium, which also occurs at the type-locality of jacksoni, but the latter with 
much stronger sculpture on the propodeal dorsum and sides of the alitrunk, and with smaller and less 
prominent clypeal teeth. 

Monomorium valtinum sp. n. 

Holotype worker. TL 1-9, HL 0-48, HW 0-40, CI 83, SL 0-32, SI 80, PW 0-28, AL 0-52. 

Mandibles unsculptured except for small hair-pits. Clypeal carinae sharply defined, raised and terminat- 
ing in two short triangular teeth at the anterior clypeal margin. Eye small, maximum diameter 0-15 x HW 
and with 3 ommatidia in the longest row. Entire eye with only 6 ommatidia, these not arranged in a 
peripheral ring which encloses centrally placed ommatidia. Promesonotum evenly but shallowly convex in 
profile, the metanotal groove feebly impressed and the propodeum sloping posteriorly behind the groove. 
Propodeal dorsum and declivity separated by an obtuse and bluntly rounded angle in profile. Propodeum 
in dorsal view with its lateral borders bluntly marginate, the surface between the marginations flat to 
shallowly transversely concave. Nodes of both petiole and postpetiole high and narrow in profile, in the 
former the distance from the spiracle to the apex of the node considerably greater than the distance from 
the spiracle to the insertion of the peduncle. In dorsal view both nodes transverse, conspicuously much 
broader than long. Cephalic dorsum unsculptured except for hair-pits and some faint sculpture immedi- 
ately behind the frontal lobes. Promesonotum dorsally glassy smooth but the propodeal dorsum very finely 
and faintly transversely striolate. Sides of alitrunk unsculptured except for the metanotum and some 
vestigial traces at about the mid-height of the mesopleuron. Petiole, postpetiole and gaster unsculptured. 
All dorsal surfaces of head and body with standing hairs present. Colour glossy light brown, yellowish 
brown in places; the appendages light brownish yellow. 

Paratype workers. TL 1-8-1-9, HL 0-47-0-48, HW 0-39-0-40, CI 81-83, SL 0-32-0-33, SI 80-83, PW 
0-28-0-29, AL 0-51-0-53 (8 measured). As holotype but maximum diameter of eye 0-13-0-15 x HW, with 
a total of 6-7 ommatidia and with 3-4 in the longest row. 

Holotype worker, Kenya: Kilifi Dist., Jilore, 29.x. 1977 (Mahnert & Perret) (MHN). 
Paratypes. 5 workers with same data as holotype (MHN; BMNH; MCZ). 

This small light brown species differs from hanneli, the only other member of this group from eastern 
Africa, by being smaller, showing less size variation, and having relatively very small eyes both in terms of 
size and of number of ommatidia present. 






SOLENOPSIS GENUS-GROUP 429 

The latinode-group 

(Figs 99, 100) 

Worker. Size variable in any given series, showing simple monophasic allometric variation. Palp formula 
3,3 (latinode). Mandibles unsculptured, with 5 teeth which decrease in size from apex to base. Median 
portion of clypeus broad and weakly bicarinate; posteriorly distinctly broader than the maximum width of 
either frontal lobe where it passes between them. Anterior clypeal margin without a pair of projecting 
teeth. Cephalic dorsum unsculptured except for hair-pits. Lateral portions of clypeus, area immediately 
behind clypeus, and area around antennal fossae mostly or entirely smooth, sometimes with vestiges of 
striolate or costulate sculpture. Eyes of moderate size, with 7-9 ommatidia in the longest row, their 
maximum diameter 0- 19-0-21 x HW. Eyes situated conspicuously in front of the midlength of the sides in 
full-face view. In profile the long axis of the eye not strongly oblique with respect to the long axis of the 
head, the eyes not reniform. Antennae with 12 segments, with a strongly developed club of 3 segments. 
Propodeal spiracle circular. Propodeal dorsum transversely sculptured and rounding into the declivity. 
Track of metanotal groove in dorsal view not transverse but anteriorly arched or even inverted V-shaped 
medially. Petiolar spiracle close to level of anterior face of node. Fine standing hairs present on all dorsal 
surfaces of head and body. 

Female. As worker but larger, the alitrunk with a full complement of flight sclerites and the head with ocelli 
present. HW slightly greater than maximum width of mesoscutum. With alitrunk in dorsal view the 
pronotum not forming part of the dorsum. Mesoscutum longer than broad. Axillary sclerites large and 
subtriangular in dorsal view, separated medially by a short impressed area between them. Parapsidal 
grooves faint. Forewing with cross-vein m-cu present. 

Male. Unknown. 

Only a single species is recognized in this group at present, latinode. The combination of characters listed 
above isolates it from all other Monomorium species-groups, and the combination of 5-dentate mandibles 
and PF 3,3 is immediately diagnostic. 

M. latinode is known from several countries bordering the Indian Ocean but most samples which are 
available for examination come from India and Sri Lanka. Its presence in Borneo, Tanzania (Pemba I.) 
and New Zealand (Wellington and Auckland, where it was found in the hold of a ship), as well as its 
occurrence on Christmas Island in the Indian Ocean and Hawaii in the Pacific (Wheeler, 1935), implies that 
latinode has tramping ability and has been spread considerably by commercial activity. The Indian 
subcontinent presumably represents its area of origin; Wilson & Taylor (1967) state that its native range 
extends from Sri Lanka to Taiwan and south to Java and Sumatra. 

Monomorium latinode Mayr 
(Figs 99, 100) 

Monomorium latinode Mayr, 1872: 152. Syntype workers, East Malaysia: Sarawak, 1865-66 (G. Doria) 

(BMNH) [examined]. 
Monomorium latinode var. bruneum Emery, 18936: 243. Syntype workers, Sri Lanka: Kandy, i— ii. 1892 

(E. Simon) (MCSN) [not seen]. Syn. n. 
Monomorium voeltzkowi Forel, 19076: 78. Syntype workers, Tanzania: Pemba I., Chake-Chake 

(A. Voeltzkow) (MHN; MCZ) [examined]. Syn. n. 

Worker. TL 2-6-3-2, HL 0-68-0-88, HW 0-52-0-75, CI 76-87, SL 0-52-0-64, SI 85-102, PW 0-36-0-50, 
AL 0-77-1-00 (20 measured). 

With the species-group characters given above. All dorsal surfaces of the head and body with numerous 
erect to suberect fine hairs. Scapes and middle and hind tibiae with numerous projecting long hairs which 
are erect to suberect; the longest of these hairs equal to or exceeding the maximum width of the scape or 
tibia from which they arise. Head and promesonotum unsculptured except for hair-pits, propodeal dorsum 
transversely finely rugulose or costulate, the sculpture sometimes faint. Petiole, postpetiole and gaster 
unsculptured. Postpetiole conspicuously swollen in profile (Fig. 100). Colour variable, ranging from 
uniform brownish yellow to uniform chestnut brown. Usually the gaster dark brown, the head and alitrunk 
brownish yellow to dirty yellow; sometimes the head darker than the alitrunk but not as dark brown as the 
gaster. Maximum diameter of eye 0-19-0-21 x HW, with 7-9 ommatidia in the longest row. Simple 



430 B. BOLTON 

allometric variation present. In the individuals used to obtain the standard measurements given above 
three trends were noticeable, as follows. 

As HW increases, SI decreases (in HW interval 0-52-0-56, SI is 102-98; in HW interval 0-57-0-67, SI is 
97-90; in HW interval >0-70, SI is <80). 

As HW increases, CI increases (in HW interval 0-52-0-57, CI is 76-79; in HW interval 0-60-0-64, CI is 
80-82; in HW interval 0-66-0-75, CI is 84-87). 

As HW increases, relative size of eye decreases (at HW 0-52, maximum diameter of eye is 0-21 x HW; at 
HW 0-61, maximum diameter of eye is 0-20 x HW; at HW 0-75, maximum diameter of eye is 0-19 x HW). 

The 3,3 palp formula and presence of 5 teeth on each mandible immediately separates latinode from all 
its Afrotropical congeners, where the PF is 2,2 or less and the maximum dental count is four. Apart from 
latinode species with 5-dentate mandibles occur in the Malagasy, Indo-Australian and Australasian 
regions, and the closest relatives of latinode will most probably have to be sought among the little known 
Monomorium species of those regions. 

In the synonymy given above I have not seen type-material of bruneum but Emery used only the uniform 
darker colour of his Sri Lankan specimens to separate them from the lighter type-series of latinode from 
Borneo. As discussed above other series show intermediate colours between these extremes, so I have 
relegated var. bruneum to the synonymy. M. latinode and voeltzkowi are absolute synonyms. 

Material examined 

Afrotropical region. Tanzania: Pemba I. {A. Voeltzkow). 

Other regions. Sri Lanka: no loc. (coll. F. Smith). India: Tamil Nadu, Mudumalai Anim. Sanct. (/. 5. 
Noyes); Mudigere (/. S. Noyes); Karnatake, Dharwad (G.R.); Nilger (coll. Donisthorpe); no loc. (coll. 
Bingham). East Malaysia: Borneo, Sarawak (G. Doria). New Zealand: Auckland (in hold of ship); 
Wellington (H. R. Pallas). Christmas I. (Indian Ocean). 

Nomen nudum 

Monomorium orientate var. africanum Forel, 1907: 78 (attributed to Mayr). 

No description was appended to the name africanum by Forel, who attributed it to Mayr. Such a name 
was never published by Mayr and no specimens bearing the name have been detected in the Forel 
collection (MHN). 

Acknowledgements 

I am indebted to the following for making types and other material freely available for my study. Without 
their help and kindness the survey could not have been undertaken. 

Dr Cesare Baroni Urbani (NMB); Dr Claude Besuchet (MHN); Dr Jean Decelle and Mrs Eliane de 
Coninck (MRAC) ; Dr Max Fischer (NMV) ; Dr Frank Koch (MNHU) ; Mr Christopher OToole (UM) ; Dr 
Roberto Poggi (MCSN); Dr Andre Prins and Ms Amanda Roux (SAM); Dr Scott R. Shaw (MCZ); Dr 
Robert W. Taylor (ANIC); Mme Janine C. Weulersse (MNHN). 

My thanks also to Dr Alan C. Marsh and Dr Christian Peeters for collecting on my behalf, to Mr Cedric 
A. Collingwood for material from his private collection, to Dr Denis Brothers for donation of material, to 
Dr Murray S. Blum for information on venoms, and last but by no means least to Professor William L. 
Brown Jr, for hours of interesting discussion over the years and for regulating the attentions of the 
Donisthorpe Prize committee. 

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SOLENOPSIS GENUS-GROUP 437 

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19146. Meddelanden fran Goteborgs Musei Zoologiska Afdeling no. 3. Fourmis du Natal et du 



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Entomologique de France 85 (1916): 279-296. 

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— 19196. Fourmis nouvelles ethiopiennes. Revue Zoologique Africaine 6: 229-240, 4 figs. 

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— 1920a. Formicides Africains et Americains nouveaux. Annates de la Societe Entomologique de France 



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SOLENOPSIS GENUS-GROUP 



439 



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Polskie Pismo Entomologiczne 41: 459-474. 



440 



B. BOLTON 




Figs 1-6 1-3, heads of workers: (1) Anillomyrma tridens, (2) Bondroitia lujae, (3) Diplomorium 
longipenne. 4-6, profiles of workers: (4) Anillomyrma tridens, (5) Bondroitia lujae, (6) Diplomorium 
longipenne. 



SOLENOPSIS GENUS-GROUP 



441 





Figs 7-15 7-11, Bondroitia lujae: (7) head of female, (8) petiole and postpetiole of female, (9) 
mesoscutum, scutellum and axillae of female, (10) profile of male head and alitrunk, (11) forewing. 
12-15, Diplomorium longipenne female: (12) forewing, (13) petiole and postpetiole, (14) head, (15) 
mesoscutum, scutellum and axillae. (Pilosity omitted except in 10.) 



442 



B. BOLTON 




Figs 16-24 16-17, Epelysidris brocha worker: (16) profile, (17) head; offset shows mandible with head 
tilted backwards. 18-24, venation in Monomorium: (18) antarcticum, (19-21) to show loss of m-cu in 
scabriceps- and destructor-groups, (22-24) to show loss of tubular veins and cu-a in (22) indicum, (23) 
fastidium, (24) pharaonis . 



SOLENOPSIS GENUS-GROUP 



443 




Figs. 25-33 Monomorium species. 25-26, heads of males in (25) salomonis-group , (26) scabriceps- and 
destructor-groups. 27-30, profile of alitrunk in females of (27) rufulum, (28) undescribed species near 
hesperium, (29) medinae, (30) advena. 31-33, worker of abyssinicum: (31) head of major (HW 1-84), 
(32) head of minor (HW 0-92), (33) profile of major. (Pilosity omitted in 25, 26, 31, 32.) 



444 



B. BOLTON 




Figs 34-44 Monomorium workers. 34-38, profiles of (34) mayri, (35) robustior, (36) rufulum, (37) westi, 
(38) albopilosum. 39, 40, petiole and postpetiole of (39) destructor, specimen with HW 0-65, (40) oscaris, 
specimen with HW 0-68. 41-44, heads of (41) robustior, (42) rufulum, (43) westi, (44) albopilosum. 
(Pilosity omitted in 39, 40.) 



SOLENOPSIS GENUS-GROUP 



445 







Figs 45-53 Monomorium workers. 45-50, profiles of (45) afrum, (46) areniphilum, (47) viator, (48) 
drapenum, (49) kitectum, (50) marshi. 51-53, heads of (51) areniphilum, (52) viator, (53) marshi. 



446 



B. BOLTON 




Figs 54-63 Monomorium workers. 54-59, profiles of (54) willowmorense , (55) vatranum, (56) phar- 
aonis, (57) setuliferum, (58) alamarum, (59) macrops. 60-63, heads of (60) pharaonis , (61) excensurae, 
(62) tynsorum, (63) boerorum. 



SOLENOPSIS GENUS-GROUP 



447 




Figs 64-76 Monomorium workers. 64-69, profiles of (64) kineti, (65) arboreum, (66) leopoldinum, (67) 
firmum, (68) vecte, (69) crawleyi. 70-73, heads of (70) exchao, (71) egens, (72) fca/ir, (73) occidentale. 
74-76, profiles of (74) katir, (75) excensurae, (76) gabrielense. 






448 



B. BOLTON 




Figs 77-90 Monomorium workers, profiles. 77, exchao, 78, binatu, 79, symmotu, 80, tablense, 81, 
rhopalocerum, 82, egens, 83, disoriente, 84, angustinode, 85, altinode, 86, arnoldi, 87, tynsorum, 88, 
fugelanum, 89, paternum, 90, lubricum. 



SOLENOPSIS GENUS-GROUP 



449 






Figs 91-100 Monomorium workers. 91, 92, profiles of (91) boerorum, (92) bequaerti. 93, head of 
thrascoleptum. 94, profile of thrascoleptum. 95, profile of modestum. 96, petiole, postpetiole and 
posterior view of latter in guineense. 97, head of invidium. 98, profile of invidium. 99, head of latinode. 
100, profile of latinode. 



450 



B. BOLTON 

Index 



Synonyms are in italics; principal page references are in bold. 



abeillei 329 
aberrans297,323 
abyssinicum 320, 321 
Adlerzia 266 
adulatrix 291 
advena 287, 329 
aequatoriale 331 , 338 
aequum 397 
affabile 374, 375 
africanum 430 

afrum 291, 329, 330, 331, 334 
alamarum 365, 366, 367 
albopilosum 329, 330, 331, 335 
algiricum 292, 329 
Allomerus 265, 271 , 272, 282 
altinode373,375 
altinode 399 
altinode-complex 373 
alvarengai 286 
amblyops 323 
anceps333,336, 337 
andrei 287, 372 
andrei 287 
Anergates 266 
angusticlava 390 
angustinode 373, 376 
Anillomyrma 265, 267, 271, 273 
Anisopheidole 265 
antarcticum 287, 288 
Antichthonidris 266, 271 , 272, 

283, 290 
antiguensis 356 
arboreum 372, 374, 377, 412 
areniphilum 329, 336 
areniphilum-complex 332 
arnoldi 373, 378 
arnoldi 422 
asmarensis 334 
atomaria 314, 327 
atomum 372 

australe 296, 323, 333, 337 
australe-complex 333 

balathir372,373,378 

basalis 324 

belli 364 

bequaerti375,379 

bequaerti-complex 374 

bevisi 374, 379, 412 

bicolor 284, 286, 329, 330, 331, 

338 
bicolor-complex 331 
bidentata283,284 
bimaculatwn 356 
bimaculatoides 356 
binatu 374, 380 
boerorum372,375,381 
boerorum 423 
boerorum-complex 375 
bondroiti 375 



Bondroitia 271 , 272, 273, 275, 404 

borlei373,381 

braunsi 375, 382 

brocha279,280 

Brownidris 265 , 266 

bruchi 286 

bntneum 429 

bulawayense 311 

bulawayensis 388 

buxtoni 329 

cabrerai 293, 360 

captator373,382 

carbo333,339 

carbonarium 372 

Carebara 265 

Carebarella265,271,286 

cekalovici 284 

Chelaner 265, 266, 283, 284, 287, 

290, 300 
chinense 288, 372 
chobauti 287, 296, 297, 323 
cinnabari 390 
clarithorax 335 
claveaui 360 
clavicorne 372 
coecum 275, 277 
coerulescens 331 , 338 
contigua 356 
continentis 274 
cooperi 372 

Corynomyrmex 287, 290, 299, 373 
cotterelli 408 
crawleyi 374, 383, 412 
criniceps 320, 321 
cryptobium 420, 421 
cyaneum 298, 372 

dakarense 331, 333, 339 
damarense 292, 294, 329, 333, 340 
decamera 273, 274 
decemarticulatus 282 
delagoense 329, 330, 332, 341 
denticulata283,284 
dentigerum 320, 321 
despecta 326 

destructor 287, 296, 323, 324 
destructor-group 289, 290, 296, 

302, 322 
dichroum 292, 294, 329 
dictator, 329, 331, 341 
Diplomorium 265, 271, 272, 273, 

276, 278, 283 
Diplorhoptrum 285 
disertum333,342 
disoriente 374, 383 
dispar 296, 326 
distinction 368 
dolatu 374, 384 
dolichops 370 



domestica 356 
donisthorpei 372 
Dorothea 266 
drapenum 329, 332, 342 
draxocum 372, 374, 385, 403 
Dyomorium 265, 266 

ebangaense 331, 366, 367 
ebeninum 372 
effractor 292, 329,330 
egens 372, 374, 385 
elgonense 422 
emeryi 323, 325 
Epelysidris271,272,279 
epinotale 323, 326 
Epixenus 287, 290, 292, 294 
Epoecus 287, 290, 298, 373 
Equestrimessor 287, 290, 297 
esharre333,343 
eslherae 397 
evansi 321 

excelsior 330, 332,344 
excensurae 374, 386, 412 
exchao372,374, 387 
exiguum 372, 375,388 
explorator 397 

falcatum 288 
falcatum-group 290, 300 
fasciatum 374, 388 
fastidium372,375,389 
faurei 388 
fieldi 372 
fingo 335 

firmum372,374,389,412 
flavescens 388 

floricola 298, 299, 372, 375, 390 
forcipatum 287 
forcipatum-group 290, 300 
fossulatum 420, 421 
fossulatum-group 267, 273, 290, 

297, 302, 420 
fragilis 356 
fridae 344 
fugax 285 

fugelanum 373, 391 
fultor 334 

gabrielense 374, 392 
geminata 285 
glabrum 320, 321 
glyciphila 360 
gracillima 287, 324 
gracillimus 287, 299 
grahamstownensis 341 
grassei 292 

guillarmodi 372, 375, 392 
guineense 292, 426 

Hagioxenus 265, 266 



SOLENOPSIS GENUS-GROUP 



451 



hanneli425,426 
hanneli-group 267, 302, 425 
hannonis 366, 368 
havilandi296,365,366,368 
havilandi-complex 366 
herero329,332,345 
hesperium 292, 294, 329 
Heteromyrmex 266 
hirsutum 331, 345 
Hokomyrmex 287, 290, 295, 321 
holothir'373,393 
hospitum 287, 298, 299, 372 
hottentota 407 
Huberia266 

ilgii 346 
impressum 390 
impurkeps 341 
indicum292,329,330 
inquictum 375. 394 
inquilina 290 
inquilinum 298 
insidiosa 29 1 
intrudens372,390 
invidium 425, 427 
/nw/Wn.s 287, 290, 298 
hokomyrmex 287, 290, 296 
italica 360 
iyenasu 374, 394 

jacksoni425,427 
javanum 288, 372 
jonesi 422 
jucundum 385 
junodi329, 330, 331,346 

kcdaharknse 326 
karawajewi 326 
katir373,395 
katir-complex 373 
kclapre375,395 
kineti 374, 396, 412 
kitectum 332, 347 

lacrymans 341 

laeve 287, 372 

laevkeps 337 

lameerei 297, 323 

Lampromyrmex 287, 290, 299, 373 

latastei 283, 284 

latinode 429 

latinode-group 302, 429 

latior 370 

leimbachi 407 

lene373,397 

leoninus 285 

leopoldinum 373, 397 

leopoldinum-complex 373 

kpincyi 336 

kvkeps 368 

libanicum 293 

liberta 360 

liliuokalanii 288 

Liomyrmex 266 

longi 329, 333 

longipenne 278, 279 



longiusculum 385 
Lophomyrmex 265 
Iubricum375,398 

Iujae275,277 

macrops 366, 369 

macrops-complex 366 

malamixtum 420, 423 

malatu374,375,399 

malatu-complex 374 

mandibularis 285 

manir373,400 

mantazenum 332, 348 

marshi329,332,349 

mavide375,400 

mayri296,323,326 

mayrianum 287, 299 

medinae 287, 292, 293. 294, 329, 

330 
mediocre 333. 349 
mediocre-complex 333 
mediterraneum 360 
Megalomyrmex 265, 267, 271 . 

272, 279, 285 
Megalomyrmex-group 265, 266 
micropacum 331 , 350 
mictilis372, 375.401 
minimum 298, 372 
minor 292, 294, 329. 330, 333, 350 
minuto 287, 288, 356 
minutissimum 4(11 
minutum 2S7. 288 
mirandum 373, 401 
M;'wra287,290,299,373 
modestum 287, 423 
modestus-group 269, 279, 285 
moeslum 426 
monardi 359 
Monomorium 265, 271, 272. 27s. 

284,287.290,300, 301 
Monomorium-group 265, 266 
monomorium 287. 288 
monomorium-group 290, 298. 330, 

371,373 
musicum372,375,402 
muticum 321 
myops 287, 298 
Myrmecinella 266 
w>>5to287,293,294 

niloticum 329 
nipponense 390 

nirvanum 333, 351 

nitidiventre 331 

Nothidris 265, 266, 271 , 272, 283, 

284. 290, 300 
Notomvrmex 284, 287, 288. 290, 

300 
notulum 366, 370 
noualhieri 281, 282, 293,329 
noxitum 374, 403 
nuptualis 375, 403 
nyasae 367 

obscuripes 293, 360 
occidentale 372, 373, 404 



ocellatum 329. 330. 332, 352 
Ochetomyrmex 266 
Oligomyrmex 265 
ominosa 324, 327 
opacior 292, 294. 329. 333, 352 
opacior 352 
opacum 331 , 353, 360 
opacum-complex 331 
ophthalmicum 332, 353 
orangiae 354 
orientale 372 
oscaris 323, 326 
osiridis329.333.354 
Oxyepoecus 265, 267, 271 , 272. 
286 

pacis 404 
Pacdalgus 265 
pallidipes373.405 
pallidum 292, 294, 329 
Paraphacota 287, 290, 293 
Parholcomyrmex 287, 290. 296. 

323 
parvinode 333. 355 
paternum 375, 405 
paucipilosa 335 
pergandei 2S7. 298. 299, 372 
personatum 33 1 , 356 
petulans 342 

Phacota271,272.281,290 
pharaonis 287, 288, 329. 330, 333, 

356 
pharaonis-complex 333 
Pharaophanes 288 
Pheidologetini 265 
Pheidologeton 265 
Pheidologeton-group 265 
poecilum 390 
pretoriensis 346 
prossae 327 

Protholcomyrmex 287, 290, 300 
pulchrum 375. 406 
pullula 336 

rahirmm329.333.358.365 
rastractum 373,406 
rhopalocerum 372, 374, 407 
rhopalocerum-complex 374 
Rhoptromyrmex 266 
robustior 296, 323,328 
robusiius 328 
rogeri287,321 
rosae372.375.408 
rothsteini 287 
rothsteini-group 290, 300 
rotundatum 372, 375, 409 
rubriceps 284 
rufescens 29 1 
rufi basis 331,338 
rufobasalis 338 

rululum 292, 294, 329, 330, 331, 
359 

saharensis275, 277 
salomonis287,291,329 



452 



B. BOLTON 



salomonis-group 290, 291, 302, 

329,331,366 
samoanum 288 
sanguinolentum 284 
santschianum 287, 296, 323 
santschiellum 360 
santschii287,291,329,330 
santschii 287,296 
scabriceps 287, 320, 321 
scabriceps-group 289, 290, 295, 

302, 320 
Schizopelta 288, 290, 300 
schultzei 372, 374,410,412 
schultzei-complex 374 
schurri 329 
semipolitus 266 
senegalense 333, 359 
senegalensis 360 
serenum 352 
sersalatum 420, 424 
setuliferum365,366, 370 
setuliferum-complex 366 
setuliferum-group 302, 365 
shilohense375,410 
shuckardi 297 
sichelii 281, 282 
smuts i 424 

Solenopsidini 265, 266 
Solenopsis265,271,285,286 
Solenopsis-group 264, 265, 266, 

269,271 
soiled 326, 328 
spectrum 375, 411 
specularis 390 
speculiceps 344 
speluncarum 374, 411, 412 
springvalense 373, 412 
sryetum 375,413 



strangulatum 374, 413 
strangulatum-complex 374 
subdentatum329,331,359 
subnitidum 329 
subopacum 287, 293, 329, 330, 

332, 360 
subopacum-complex 332 
sudanicum 401 
surcoufi 287, 293, 360 
sutu 329, 333, 361 
Syllophopsis 265, 287, 290, 297 
symmotu 374, 414 
syriacum 292 

tablense 374,414 
taedium 375, 415 
talbotae 298 
talpa287,298,420,421 
tanysum 374, 416 
tchelichofi 362 
tchelichofi-complex 332 
termitarium 333, 337, 362 
thales 335 
thrascoleptum 424 
torvicte372,375,401,416 
trake375,417 
Tranopelta265,266,323 
Tranopeltoides 266 
transwaalensis 423 
Trichomyrmex 287, 290, 296 
tridens 274 
Trigonogaster 265 
triviale 372 
tropicale 331, 338 
turneri 284 
tynsorum373,417 

uelense 331, 338 



utuense 338 
unicolor 340 
unifasciata 356 

vaguum 375, 418 
valtinum 428 
vas tutor 288, 356 
vatranum 332, 362 
vecte374,412,419 
venustum 292, 294, 329 
vexator 324 

viator 329, 330, 332, 363 
viator-complex 332 
viridum 372 
voeltzkowi 296, 429 
vogeli 282 

Vollenhovia 265, 266 
vonatu373,420 

westi329,331,363 
Wheeleria2%l ,29\ 
Wheeleriella 287, 290, 291 
wheelerorum 372 
whitei 321 

willowmorense 332, 364 
willowmorensis 364 
wroughtoni 292, 329, 333 
wroughtoni 291 , 292 
wroughtonianum 321 

xanthognathum 365, 366, 371 
Xenoaphaenogaster 290 
Xenomyrmex 266 
Xenhyboma 287, 290, 293 
Xeromyrmex 287, 290, 294, 297, 
330 

zulu 333, 365 



British Museum (Natural History) 

Milkweed butterflies: their cladistics and biology 

P. R. Ackery & R. I. Vane-Wright 

The Danainae, a subfamily of the Nymphalidae, contains only some 150 species, yet aspects of 
their biology have stimulated far more attention than can be justified by species numbers 
alone. In recent years, an expansive literature has grown, considering aspects of their 
courtship and pre-courtship behaviour, migration, larval hostplant associations, mimicry and 
genetics. The popularity of danaines among biologists can certainly be attributed to this 
combination, within one small group, of so many of the factors that make butterflies such an 
interesting group to study. The obvious need to place this wealth of biological data within an 
acceptable systematic framework provided the impetus for this volume. 

Started eight years ago within the conventions of evolution by natural selection and 
Hennig's phylogenetic systematics, the book is now largely about natural history (what the 
animals have and do, where they live and how they develop) and natural groups - as revealed 
by a form of analysis approaching that practised by the new school of 'transformed cladistics'. 
The authors have prepared a handbook that will appeal to a wide range of biologists, from 
museum taxonomists to field ecologists. 

425 pp, 12 pp colour, 73 b/w plates, line and graphic illustrations, maps, extensive bibliography. 
ISBN 565 00893 5. 1984. Price £50. 



Titles to be published in Volume 54 



Studies on the Old World species of Holothrips (Thysanoptera: Phlaeothripidae) 

By S. Okajima 

Spectacles and Silver Ys: a synthesis of the systematics, cladistics and biology of the Plusiinae 
(Lepidoptera: Noctuidae) 

By I. J.Kitching 

A review of the Solenopsis genus-group and revision of Afrotropical Monomorium Mayr 
(Hymenoptera: Formicidae) 

By B.Bolton 



Photoset by Rowland Phototypesetting Ltd, Bury St Edmunds, Suffolk 
Printed in Great Britain by Henry Ling Ltd, Dorchester